The present invention is a light weight low profile variable shotgun bore choke that is easily manually adjusted by the user. To minimize the choke profile, the choke is connected to the shotgun through a threaded connection within the muzzle bore. External threads on a choke inner sleeve are configured to mate with standard threads found in existing prior shotgun barrel muzzles or with custom threads specifically formed. By using a threaded connection internal to the gun barrel, the overall radial dimensions of the choke are minimized thereby reducing the profile visible to the user. Weight is also reduced by a design which reduces radial dimensions and by use of light weight materials. The choke is adjusted by the user by manually rotating an outer adjustment sleeve with respect to an inner bore sleeve which is fixed to the shotgun barrel. The adjustment sleeve rotates through a range of choke conditions between two physical stops. Various choke conditions are indicated by circumferential grooves that are easily viewed from any location around the choke.

The present invention pertains to devices for altering the shot pattern obtainable from shotguns. In particular, the invention pertains to adjustable chokes for providing variable shot pattern with a single shotgun. This function has been addressed by a great variety of prior devices. Typically, one or more vents, barrel wall constrictions or enlargements and other structures are provided at the shotgun muzzle to compress or expand shot passing through the barrel. While such prior devices are somewhat successful in controlling shot pattern, they typically result in a firearm which is difficult to use or which detracts from the performance of the shotgun.
In both competition shooting and hunting, the additional weight of a shot pattern altering xe2x80x9cchokexe2x80x9d structure at the end of the gun barrel can render a shotgun more difficult to move and aim. In addition, in order to accomplish the desired functions, prior variable choke devices typically have radial dimensions significantly greater than the associated shotgun barrel. Because these larger structures are at the end of the gun barrel, the result is an obstruction to the user""s sight when aiming at a target. In addition, prior variable chokes require too much attention by the user to be successfully used in a hunting environment, where the user may have to quickly make adjustments to shot pattern depending upon rapidly changing events. These adjustments may also have to be accomplished in low light. Prior devices which require careful visual scrutiny of adjustment markings are likely to be improperly used in such conditions. The prior device disclosed in U.S. Pat. No. 2,629,958 to W. F. Roper et al. provides examples of these failings. The Roper device is relatively large: projecting outward from the outer diameter of the gun barrel to which it is mounted. The Roper device also provides adjustment indicia in the form of surface lettering which is likely to be difficult to use in low light conditions. Another example of this type of design is presented in U.S. Pat. No. 2,634,537 to R. V. Velez et al. What is needed is a low profile, low weight adjustable shotgun choke which does not interfere with the effective use of the connected shotgun and may be quickly adjusted without the need for careful scrutiny.
The present invention is a light weight low profile bore choke that is easily manually adjusted by the user. To minimize the choke profile, the choke is connected to the shotgun through a threaded connection within the muzzle. External threads on a choke inner sleeve are configured to mate with standard threads found in existing prior shotgun barrel muzzles or with custom threads specifically formed. By using a threaded connection internal to the gun barrel, the overall radial dimensions of the choke are minimized thereby reducing the profile visible to the user.
The choke is adjusted by the user by manually rotating an outer adjustment sleeve with respect to an inner bore sleeve which is fixed to the shotgun barrel. The adjustment sleeve has longitudinal grooves to increase grip. The adjustment sleeve has internal threads which mate with external threads on the bore sleeve. When the adjustment sleeve is rotated, a tapered adjustment surface within the adjustment sleeve forces elongated fingers on the bore sleeve radially inward to form a bore constriction. This constriction converges in the direction of the mouth of the choke to cause the choking effect. Various taper designs including those known in the prior art are applicable to the present invention. The adjustment sleeve rotates between two physical stops to provide the full range of adjustment. Indicia are also provided to provide visual indication of the choke condition. These are preferably circumferential grooves that are easily visible from any position surrounding the choke. One physical stop is formed by a spring clip that is located between the bore sleeve and the adjustment sleeve. It is secured rotationally to the bore sleeve and biased against the inside of the adjustment sleeve. As the adjustment sleeve is rotated, a clip end drags against the adjustment sleeve until aligning with an aperture in the adjustment sleeve. The adjustment sleeve is prevented from being moved past an open condition by the interference of the clip end in the aperture. This operation of the spring clip increases safety of the choke in that the adjustment sleeve cannot be accidentally loosened or removed from the bore sleeve. To reduce weight, the adjustment sleeve is preferably formed of titanium. Additional advantages of the invention will become obvious from the following details and figures.


Compositions containing:

The present invention relates to polycarbonate compositions that have been rendered flame-resistant with phosphorus compounds, that have an excellent mechanical property spectrum, a good heat resistance, an improved flame-proofing effect and improved flow behavior (processing behavior).
Compositions containing:
I. at least two components selected from the group comprising aromatic poly(ester) carbonates, graft polymers of one or more vinyl monomers on one or more graft bases having a glass transition temperature of  less than 10xc2x0 C., a thermoplastic vinyl (co)polymer, or poly(alkylene terephthalate) as well as
II. 0.5 to 25 parts by weight of a mixture of phosphorus compounds of the general formula (I)
with the proviso that the composition contains at least 2 phosphorus compounds of the formula (I) in which X or one or more radicals R1, R2, R3 and R4 is/are different.
U.S. Pat. No. 5,061,745 describes molding compositions of an aromatic polycarbonate, graft polymer and monophosphate. Although these mixtures exhibit a good flow behavior and a good flame-proofing effect, nevertheless they often do not have the required high degree of heat resistance. Moreover, on account of their volatility, monophosphates do not meet specific processing conditions for the formation of an effective coating.
In EP-A 0 640 655 molding compositions of aromatic polycarbonate, styrene-containing copolymers and graft polymers are described that may be rendered flame-resistant with monomeric and/or oligomeric phosphorus compounds. The aforementioned disadvantages may arise on account of the content of monomeric phosphorus compounds.
EP-A 747 424 describes the use of a combination of phosphate having a molecular weight of approximately 500 to 2,000 and phosphate having a molecular weight of approximately 2,300 to 11,000 as flame-proofing agent in thermoplastic resins, a large number of thermoplastic resins being listed. On account of the high molecular weight of the flame-proofing agents deficiencies in the flame-proofing effect can be expected.
In EP-A-0363608 flame-resistant polymer mixtures are described, consisting of aromatic polycarbonate, styrene-containing copolymer or graft copolymer as well as an oligomeric phosphate as flame-proofing additive, wherein frequently the required property combination of a good flame-proofing effect and good processing behavior is not achieved.
The object of the present invention is accordingly to provide polycarbonate compositions that have an improved flame-proofing effect, a high heat resistance, and improved flow behavior (processing behavior) as well as good mechanical properties.
It has now surprisingly been found that by the use of mixtures of oligophosphates with various structures, molding compositions/molded articles can be obtained that have the desired property profile.
The present invention provides compositions containing:
I. at least two components selected from the group comprising aromatic poly(ester) carbonates, graft polymers of one or more vinyl monomers on one or more graft bases having a glass transition temperature of  less than 10xc2x0 C., and thermoplastic vinyl (co)polymer, as well as
II. 0.5 to 25 parts by weight of a mixture of phosphorus compounds of the general formula (I)
wherein
X denotes a mononuclear or polynuclear aromatic radical with 6 to 30
C atoms,
R1, R2, R3 and R4 independently of one another denote optionally halogenated C1-C8 alkyl, or C5-C6 cycloalkyl, C6-C20 aryl or C7-C12 aralkyl in each case optionally substituted by halogen and/or C1-C4 alkyl,
n independently of one another denotes 0 or 1, preferably 1,
q denotes 0.5 to 30,
with the proviso that the composition contains at least 2 phosphorus compounds of the formula (I) in which X or one or more radicals R1, R2, R3 and R4 are different and wherein the sum of the parts by weight of the components is 100.
The present invention preferably provides compositions containing:
A) 5 to 95 parts by weight, preferably 10 to 90 parts by weight, particularly preferably 20 to 80 parts by weight of aromatic polycarbonate and/or polyester carbonate
B) 1 to 60 parts by weight, preferably 1 to 40 parts by weight, particularly preferably 2 to 30 parts by weight, of at least one graft polymer of
B.1 5 to 95 wt. %, preferably 20 to 60 wt. % of one or more vinyl monomers on
B.2 5 to 95 wt. %, preferably 40 to 80 wt. % of one or more graft bases having a glass transition temperature of  less than 10xc2x0 C., preferably 0xc2x0 C., particularly preferably  less than xe2x88x9220xc2x0 C.,
C) 0 to 50 parts by weight, preferably 1 to 30 parts by weight, particularly preferably 2 to 25 parts by weight of thermoplastic vinyl (co)polymer and/or thermoplastic poly(alkylene terephthalate)
D) 0.5 to 25 parts by weight, preferably 1 to 18 parts by weight, particularly preferably 2 to 15 parts by weight of a phosphorus compound of the general formula (I)
xe2x80x83wherein
X denotes a mononuclear or polynuclear aromatic radical with 6 to 30 C atoms,
R1, R2, R3 and R4 independently of one another denote optionally halogenated C1-C8 alkyl, or C5-C6 cycloalkyl, C6-C20 aryl or C7-C12 aralkyl in each case optionally substituted by halogen and/or C1-C4 alkyl,
n independently of one another denotes 0 or 1, preferably 1,
q denotes 1 to 30,
E) 0.05 to 5 parts by weight, preferably 0.1 to 1 part by weight, particularly preferably 0.1 to 0.5 part by weight of fluorinated polyolefin
with the proviso that the composition contains at least 2 phosphorus compounds of the formula (I) in which X or one or more radicals R1, R2, R3 and R4 are different and wherein the sum of the parts by weight is 100.
Component A
Suitable aromatic polycarbonates and/or aromatic polyester carbonates of component A according to the invention are known in the literature or can be produced by methods known in the literature (for the production of aromatic polycarbonates see for example Schnell, xe2x80x9cChemistry and Physics of Polycarbonatesxe2x80x9d, Interscience Publishers, 1964, as well as DE-AS 1 495 626, DE-OS 2 232 877, DE-A 2 703 376, DE-A 2 714 544, DE-A 3 000 610, DE-A 3 832 396; for the production of aromatic polyester carbonates see for example DE-A 3 077 934).
The production of aromatic polycarbonates is carried out for example by reacting diphenols with carbonic acid halides, preferably phosgene and/or with aromatic dicarboxylic acid dihalides, preferably benzenedicarboxylic acid dihalides, by the phase boundary process, optionally with the use of chain terminators, for example monophenols, and optionally with the use of trifunctional or more than trifunctional branching agents, for example triphenols or tetraphenols.
Diphenols for the production of the aromatic polycarbonates and/or aromatic polyester carbonates are preferably those of the formula (II)
wherein
A1 denotes a single bond, C1-C5 alkylene, C2-C5 alkylidene, C5-C6 cycloalkylidene, xe2x80x94Oxe2x80x94, xe2x80x94SOxe2x80x94, xe2x80x94COxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94SO2xe2x80x94, C6-C12 arylene, which may be condensed with further aromatic rings optionally containing heteroatoms, or a radical of the formula
or a radical of the formula (IV)
B independently of one another denotes C1-C8 alkyl, preferably C1-C4 alkyl, in particular methyl, halogen, preferably chlorine and/or bromine, C6-C10 aryl, preferably phenyl, C7-C12 aralkyl, phenyl-C1-C4-alkyl, preferably benzyl
x is in each case independently of one another 0, 1 or 2,
p is 1 or 0, and
R6 and R7 may be chosen individually for each Z, and independently of one another denote hydrogen or C1-C6 alkyl, preferably hydrogen, methyl and/or ethyl,
Z denotes carbon, and
m is an integer from 4 to 7, preferably 4 or 5,
with the proviso that on at least one atom Z R6 and R7 are both simultaneously alkyl.
Preferred diphenols are hydroquinone, resorcinol, 4,4xe2x80x2-dihydroxydiphenyl, bis-(hydroxyphenyl)-C1-C5-alkanes, bis-(hydroxyphenyl)-C5-C6-cycloalkanes, bis-(hydroxyphenyl)-ethers, bis-(hydroxyphenyl)-sulfoxides, bis-(hydroxyphenyl)-ketones, bis-(hydroxyphenyl)-sulfones, and xcex1,xcex1-bis-(hydroxyphenyl)-diisopropylbenzenes such as their nuclear-brominated and/or nuclear-chlorinated derivatives.
Particularly preferred diphenols are 4,4xe2x80x2-diphenylphenol, bisphenol A, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 1,1-bis(4-hydroxyphenyl)-cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 4,4xe2x80x2-dihydroxydiphenyl sulfide, 4,4xe2x80x2-dihydroxydiphenyl sulfone as well as their dibrominated and tetrabrominated or chlorinated derivatives, such as for example 2,2-bis-(3-chloro-4-hydroxyphenyl)propane, 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)propane or 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)propane.
2,2-bis-(4-hydroxyphenyl)propane (bisphenol A) is particularly preferred.
The diphenols may be used individually or as arbitrary mixtures.
The diphenols are known in the literature or can be obtained by processes known in the literature.
Suitable chain terminators for the production of the thermoplastic, aromatic polycarbonates include for example phenol, p-chlorophenol, p-tert, -butylphenol or 2,4,6-tribromophenol, as well as long-chain alkylphenols such as 4-(1,3-tetramethylbutyl)phenol according to DE-OS 2 842 005, or monoalkylphenols or dialkylphenols with a total of 8 to 20 C atoms in the alkyl substituents, such as 3,5-di-tert.-butylphenol, p-iso-octylphenol, p-tert.-octylphenol, p-dodecylphenol, and 2-(3,5-dimethylheptyl)phenol and 4-(3,5-dimethylheptyl)phenol. The amount of chain terminators used is generally between 0.5 mole % and 10 mole %, referred to the molar sum of the diphenols used in each case.
The thermoplastic aromatic polycarbonates have mean, weight average molecular weights (Mw, measured for example by ultracentrifugation or light-scattering measurements) of 10,000 to 200,000, preferably 20,000 to 80,000.
The thermoplastic, aromatic polycarbonates may be branched in a known manner, and more specifically preferably by the incorporation of 0.05 to 2.0 mole %, referred to the sum of the diphenols used, of compounds having 3 or more functionalities, for example those with three or more than three phenolic groups.
Also suitable are homopolycarbonates as well as copolycarbonates. For the production of copolycarbonates according to the invention, as component A there may also be used 1 to 25 wt. %, preferably 2.5 to 25 wt. % (referred to the total amount of diphenols used) of polydiorganosiloxanes with hydroxy-aryloxy terminal groups. These are known (see for example U.S. Pat. No. 3,419,634) or can be produced by methods known in the literature. The production of polydiorganosiloxane-containing copolycarbonates is described for example in DE-OS 3 334 782.
Preferred polycarbonates include, in addition to bisphenol A homopolycarbonates, also the copolycarbonates of bisphenol A with up to 15 mole %, referred to the molar sums of diphenols, of diphenols other than preferred and/or particularly preferred diphenols, especially up to 15 mole % of 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane.
Aromatic dicarboxylic acid dihalides for the production of aromatic polyester carbonates are preferably the diacid dichlorides of isophthalic acid, terephthalic acid, diphenylether-4,4xe2x80x2-dicarboxylic acid and naphthalene-2,6-dicarboxylic acid.
Particularly preferred are mixtures of the diacid dichlorides of isophthalic acid and terephthalic acid in a ratio of between 1:20 and 20:1.
In the production of polyester carbonates a carbonic acid halide, preferably phosgene, is in addition co-used as bifunctional acid derivative.
Suitable chain terminators for the production of the aromatic polyester carbonates include, apart from the already mentioned monophenols, also their chlorinated carbonic acid esters as well as the acid chlorides of aromatic monocarboxylic acids, which may optionally be substituted by C1-C22 alkyl groups or by halogen atoms, as well as aliphatic C2-C22 monocarboxylic acid chlorides.
The amount of chain terminators is in each case 0.1 to 10 mole %, referred in the case of phenolic chain terminators to moles of diphenols, and in the case of monocarboxylic acid chloride chain terminators to moles of dicarboxylic acid dichlorides.
The aromatic polyester carbonates may also include incorporated aromatic hydroxycarboxylic acids.
The aromatic polyester carbonates may be linear as well as branched in a known manner (see in this connection also DE-OS 2 940 024 and DE-OS 3 007 934).
As branching agents there may be used for example trifunctional or polyfunctional carboxylic acid chlorides such as trimesic acid trichloride, cyanuric acid trichloride, 3,3xe2x80x2-4,4xe2x80x2-benzophenone tetracarboxylic acid tetrachloride, 1,4,5,8-naphthalene-tetracarboxylic acid tetrachloride or pyromellitic acid tetrachloride in amounts of 0.01 to 1.0 mole % (referred to the dicarboxylic acid dichlorides that are used), or trifunctional or polyfunctional phenols such as phloroglucinol, 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptene-2,4,4-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptane, 1,3,5-tri-(4-hydroxyphenyl)-benzene, 1,1,1-tri-(4-hydroxyphenyl)-ethane, tri-(4-hydroxyphenyl)-phenylmethane, 2,2-bis[4,4-bis-(4-hydroxyphenyl)-cyclohexyl]-propane, 2,4-bis-(4-hydroxyphenylisopropyl)-phenol, tetra-(4-hydroxyphenyl)-methane, 2,6-bis-(2-hydroxy-5-methylbenzyl)-4-methylphenol, 2-(4-hydroxy-phenyl)-2-(2,4-dihydroxyphenyl)-propane, tetra-(4-[4-hydroxyphenylisopropyl]-phenoxy)-methane, 1,4-bis-[4,4xe2x80x2-dihydroxytriphenyl)-methyl]-benzene, in amounts of 0.01 to 1.0 mole %, referred to the diphenols that are used. Phenolic branching agents may be added together with the diphenols, while acid chloride branching agents may be added together with the acid dichlorides.
In the thermoplastic, aromatic polyester carbonates the proportion of carbonate structural units may be varied as desired.
Preferably the proportion of carbonate groups is up to 100 mole %, in particular up to 80 mole %, particularly preferably up to 50 mole %, referred to the sum total of ester groups and carbonate groups.
The ester fraction as well as the carbonate fraction of the aromatic polyester carbonates may be present in the form of blocks or may be statistically distributed in the polycondensate.
The relative solution viscosity (xcex7rel.) of the aromatic polyester carbonates is in the range 1:18 to 1.4, preferably 1.22 to 1.3 (measured in solutions containing 0.5 g of polyester carbonate in 100 ml of methylene chloride solution at 25xc2x0 C.).
The thermoplastic, aromatic polycarbonates and polyester carbonates may be used alone or in arbitrary mixtures with one another.
Component B
Graft polymers constitute the component B according to the invention. These polymers include graft copolymers with rubber-elastic properties that may be obtained from at least 2 of the following monomers: chloroprene, butadiene-1,3, isoprene, styrene, acrylonitrile, ethylene, propylene, vinyl acetate and (meth)acrylic acid esters with 1 to 18 C atoms in the alcohol component; i.e. polymers such as are described for example in xe2x80x9cMethoden der Organischen Chemiexe2x80x9d (Houben-Weyl), Vol. 14/1, Georg Thieme-Verlag, Stuttgart 1961, pp. 393-406, and in C. B. Bucknall, xe2x80x9cToughened Plasticsxe2x80x9d, Appl. Science Publishers, London 1977. Preferred polymers B are partially crosslinked and have gel contents of over 20 wt. %, preferably over 40 wt. %, in particular over 60 wt. %.
Preferred graft polymers B comprise graft polymers of:
B.1 5 to 95 parts by weight, preferably 30 to 80 parts by weight, of a mixture of
B.1.1 50 to 99 parts by weight of styrene, xcex1-methylstyrene, halogen-nuclear-substituted or methyl-nuclear-substituted styrenes, methyl methacrylate or mixtures of these compounds, and
B.1.2 1 to 50 parts by weight of acrylonitrile, methacrylonitrile, methyl methacrylate, maleic anhydride, C1-C4 alkyl-substituted and/or N-phenyl-substituted maleimides or mixtures of these compounds on
B.2 5 to 95 parts by weight, preferably 20 to 70 parts by weight, of a polymer based on diene and/or alkyl acrylate and having a glass transition temperature of below xe2x88x9210xc2x0 C.,
wherein the amounts of B.1 and B.2 refer to 100 parts by weight of B, and the amounts of B.1.1 and B.1.2 refer to 100 parts by weight of B.1.
Preferred graft polymers B are for example bases B.2 such as polybutadienes, polyisoprenes, butadiene/styrene or butadiene/acrylonitrile copolymers and acrylate rubbers grafted with styrene and/or acrylonitrile and/or (meth)acrylic acid alkyl esters; i.e. copolymers of the type described in DE-A 1 694 173 (=U.S. Pat. No. 3,564,077); polybutadienes, butadiene/styrene or butadiene/acrylonitrile copolymers, polyisobutenes or polyisoprenes grafted with acrylic or methacrylic acid alkyl esters, vinyl acetate, acrylonitrile, styrene and/or alkylstyrenes, such as are described for example in DE-A 2 348 377 (=U.S. Pat. No. 3,919,353). Particularly preferred graft bases are polybutadienes that may contain up to 50 wt. %, preferably up to 30 wt. % of other monomers selected from the group comprising styrene, acrylonitrile or acrylic or methacrylic acid C1-C4 alkyl esters or mixtures thereof.
Particularly preferred polymer B are for example ABS polymers, such as are described for example in DE-A 2 035 390 (=U.S. Pat. No. 3,644,574) or in DE-A 2 248 242 (=GB-A 1 409 275).
Further particularly preferred graft polymer B may be obtained by grafting
xcex1 10 to 70 wt. %, preferably 15 to 50 wt. %, in particular 20 to 40 wt. %, relative to the weight of graft polymer B, of at least one (meth)acrylic acid ester or 10 to 70 wt. %, preferably 15 to 50 wt. %, in particular 20 to 40 wt. % of a mixture of 10 to 50 wt. %, preferably 20 to 35 wt. %, relative to the weight of the mixture, of acrylonitrile or (meth)acrylic acid esters and 50 to 90 wt. %, preferably 65 to 80 wt. %, relative to the weight of the mixture, of styrene, as graft base B.1 on
xcex2 30 to 90 wt. %, preferably 50 to 85 wt. %, in particular 60 to 80 wt. %, relative to the weight of the graft polymer B, of a butadiene polymer containing at least 50 wt. %, relative to the weight of xcex2, of butadiene radicals as graft base B.2.
The gel content of the graft base xcex2 is in general at least 20 wt. %, preferably 40 wt. % (measured in toluene), the degree of grafting G is 0.15 to 0.55, and the mean particle diameter d50 of the graft polymer B.2 is 0.05 to 2 xcexcm, preferably 0.1 to 0.6 xcexcm.
(Meth)acrylic acid esters xcex1 are esters of acrylic acid or methacrylic acid with monohydric alcohols containing 1 to 18 C atoms. Particularly preferred are methyl methacrylate, ethyl methacrylate and propyl methacrylate, n-butyl acrylate, t-butyl acrylate and t-butyl methylacrylate.
The graft base xcex2 may contain, in addition to butadiene radicals, also up to 50 wt. %, relative to the weight of xcex2, of radicals of other ethylenically unsaturated monomers such as styrene, acrylonitrile, esters of acrylic acid or methacrylic acid with 1 to 4 C atoms in the alcohol component (such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate), vinyl esters and/or vinyl ethers. The preferred graft base xcex2 consists of pure polybutadiene.
The degree of grafting G denotes the weight ratio of grafted-on graft monomers to the graft base and is dimensionless.
The mean particle diameter d50 is the diameter above and below which in each case 50 wt. % of the particles lie, and may be determined by means of ultracentrifuge measurements (W. Scholtan, H. Lange, Kolloid, Z. and Z. Polymere 250 (1972), 782-796).
Particularly preferred polymer B are for example also graft polymers of
xcfx84. 20 to 90 wt. %, relative to the weight of component B, of acrylate rubber having a glass transition temperature of  less than xe2x88x9220xc2x0 C. as graft base B.2 and
xcex4 10 to 80 wt. %, relative to the weight of component B, of at least one polymerizable, ethylenically unsaturated monomer as graft monomer B.1.
The acrylate rubbers xcfx84 of the polymers B are preferably polymers of acrylic acid alkyl esters, optionally with up to 40 wt. %, relative to the weight of xcfx84, of other polymerizable, ethylenically unsaturated monomers. The preferred polymerizable acrylic acid esters include C1-C8 alkyl esters, for example methyl, ethyl, butyl, n-octyl and 2-ethylhexyl esters; halogenated alkyl esters, preferably halogenated-C1-C8-alkyl esters such as chloroethyl acrylate, as well as mixtures of these monomers.
Monomers with more than one polymerizable double bond may be co-polymerized for the crosslinking. Preferred examples of crosslinking monomers are esters of unsaturated monocarboxylic acids with 3 to 8 C atoms and unsaturated monohydric alcohols with 3 to 12 C atoms or saturated polyols with 2 to 4 OH groups and 2 to 20 C atoms, such as for example ethylene glycol dimethacrylate, allyl methacrylate; multiply unsaturated heterocyclic compounds, such as for example trivinyl cyanurate and triallyl cyanurate; polyfunctional vinyl compounds such as divinylbenzenes and trivinylbenzenes; as well as triallyl phosphate and diallyl phthalate.
Monomers that are preferably crosslinking include allyl methacrylate, ethylene glycol dimethacrylate, diallyl phthalate and heterocyclic compounds that contain at least 3 ethylenically unsaturated groups.
Particularly preferred crosslinking monomers are the cyclic monomers triallyl cyanurate, triallyl isocyanurate, trivinyl cyanurate, triacryloylhexahydro-s-triazine, and triallylbenzenes.
The amount of the crosslinking monomers is preferably 0.02 to 5 wt. %, in particular 0.05 to 2 wt. %, relative to the weight of graft base xcfx84.
In the case of cyclic crosslinking monomers containing at least 3 ethylenically unsaturated groups, it is advantageous to restrict the amount to below 1 wt. % of the graft base xcfx84.
Preferably xe2x80x9cotherxe2x80x9d polymerizable ethylenically unsaturated monomers that in addition to the acrylic acid esters may optionally serve for the production of the graft base xcfx84 include for example acrylonitrile, styrene, xcex1-methylstyrene, acrylamides, vinyl C1-C6 alkyl ethers, methyl methacrylate, and butadiene. Preferred acrylate rubbers as graft base xcfx84 are emulsion polymers that have a gel content of at least 60 wt. %.
Further suitable graft bases according to B.2 are silicone rubbers with graft-active sites, such as are described in DE-A 3 704 657, DE-A 3 704 655, DE-A 3 631 540 and DE-A 3 631 539.
The gel content of the graft base B.2 is measured at 25xc2x0 C. in dimethylformamide (M. Hoffmann, H. Krxc3x6mer, R. Kuhn, Polymeranalysis I and II, Georg Thieme-Verlag, Stuttgart 1977).
The graft polymers B may be produced according to known methods such as bulk, suspension, emulsion or bulk-suspension methods.
Since in the graft reaction the graft monomers are, as is known, not necessarily completely grafted onto the graft base, according to the invention the term graft polymers B is understood to mean only those products that are obtained by polyreaction of the graft monomers on the graft base.
The mean particle diameter d50 is the diameter above and below which in each case 50 wt. % of the particles lie, and may be determined by means of ultracentrifuge measurements (W. Scholtan, H. Lange, Kolloid, Z. and Z. Polymere 250 (1972), 782-796).
Component C
The component C comprises one or more thermoplastic vinyl (co)polymers C.1 and/or polyalkylene terephthalates C.2.
Suitable as vinyl (co)polymers C.1 are polymers of at least one monomer from the group comprising vinyl aromatic compounds, vinyl cyanides (unsaturated nitriles), (meth)acrylic acid (C1-C8) alkyl esters, unsaturated carboxylic acids as well as derivatives (such as anhydrides and imides) of unsaturated carboxylic acids. Particularly suitable are (co)polymers of
C.1.1 50 to 99 parts by weight, preferably 60 to 80 parts by weight of vinyl aromatic compounds and/or nuclear-substituted vinyl aromatic compounds (such as for example styrene, xcex2-methylstyrene, p-methylstyrene, p-chlorostyrene) and/or methacrylic acid (C1-C8) alkyl esters (such as for example methyl methacrylate, ethyl methacrylate), and
C.1.2 1 to 50 parts by weight, preferably 20 to 40 parts by weight of vinyl cyanides (unsaturated nitriles) such as acrylonitrile and methacrylonitrile and/or (meth)acrylic acid (C1-C8) alkyl esters (such as for example methyl methacrylate, n-butyl acrylate, t-butyl acrylate) and/or unsaturated carboxylic acids (such as maleic acid) and/or derivatives (such as anhydrides and imides) of unsaturated carboxylic acids (for example maleic anhydride and N-phenylmaleimide).
The (co)polymers C.1 are resin-like, thermoplastic and rubber-free.
Particularly preferred is the copolymer of C.1.1 styrene and C.1.2 acrylonitrile, wherein the parts by weight relate to 100 parts by weight of C.1.
The (co)polymers according to C.1 are known and may be produced by free-radical polymerisation, in particular by emulsion, suspension, solution or bulk polymerisation. The (co)polymers preferably have molecular weights {overscore (M)}w (weight average, determined by light scattering or sedimentation) of between 15,000 and 200,000.
The polyalkylene terephthalates of the component C.2 are reaction products of aromatic dicarboxylic acids or their reactive derivatives, such as dimethyl esters or anhydrides, and aliphatic, cycloaliphatic or araliphatic diols as well as mixtures of these reaction products.
Preferred polyalkylene terephthalates contain at least 80 mole %, preferably at least 90 mole %, referred to the dicarboxylic acid component, of terephthalic acid radicals, and at least 80 mole %, preferably at least 90 mole %, referred to the diol component, of ethylene glycol radicals and/or butanediol-1,4 radicals.
The preferred polyalkylene terephthalates may contain, in addition to terephthalic acid radicals, also up to 20 mole %, preferably up to 10 mole %, of radicals of other aromatic or cycloaliphatic dicarboxylic acids with 8 to 14 C atoms or aliphatic dicarboxylic acids with 4 to 12 C atoms, such as for example radicals of phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, 4,4xe2x80x2-diphenyldicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, cyclohexanediacetic acid.
The preferred polyalkylene terephthalates may contain, in addition to ethylene glycol radicals or butanediol-1,4 radicals, also up to 20 mole %, preferably up to 10 mole %, of other aliphatic diols with 3 to 12 C atoms or cycloaliphatic diols with 6 to 21 C atoms, for example radicals of propanediol-1,3,2-ethylpropanediol-1,3, neopentyl glycol, pentanediol-1,5, hexanediol-1,6, cyclohexanedimethanol-1,4,3-ethylpentanediol-2,4,2-methylpentanediol-2,4,2,2,4-trimethylpentanediol-1,3,2-ethylhexanediol-1,3,2,2-diethylpropanediol-1,3, hexanediol-2,5,1,4-di-(xcex2-hydroxyethoxy)-benzene, 2,2-bis-(4-hydroxycyclohexyl)-propane, 2,4-dihydroxy-1,1,3,3-tetramethylcyclobutane, 2,2-bis-(4-xcex2-hydroxyethoxyphenyl)-propane and 2,2-bis-(4-hydroxypropoxyphenyl)-propane (DE-OS 2 407 674, 2 407 776, 2 715 932).
The polyalkylene terephthalates may be branched by incorporating functional amounts of trihydric or tetrahydric alcohols or tribasic or tetrabasic carboxylic acids, for example according to DE-OS 1 900 270 and U.S. Pat. No. 3,692,744. Examples of preferred branching agents are trimesic acid, trimellitic acid, trimethylolethane and trimethylolpropane, and pentaerythritol.
Particularly preferred are polyalkylene terephthalates that have been produced simply from terephthalic acid and its reactive derivatives (for example its dialkyl esters) and ethylene glycol and/or butanediol-1,4, and mixtures of these polyalkylene terephthalates.
Mixtures of polyalkylene terephthalates contain 1 to 50 wt. %, preferably 1 to 30 wt. %, of polyethylene terephthalate, and 50 to 99 wt. %, preferably 70 to 99 wt. %, of polybutylene terephthalate.
The polyalkylene terephthalates that are preferably used generally have an intrinsic viscosity of 0.4 to 1.5 dl/g, preferably 0.5 to 1.2 dl/g, measured in phenol/o-dichlorobenzene (1:1 parts by weight) at 25xc2x0 C. in, for instance, an Ubbelohde viscosimeter.
The polyalkylene terephthalates may be produced by known methods (see for example Kunststoff-Handbuch, Vol. VIII, p. 695 ff, Carl-Hanser-Verlag, Munich 1973).
Component D
The molding compositions according to the invention contain as flame-proofing agent at least one phosphorus compound of the formula (I-a)
wherein the radicals R1, R2, R3 and R4, and n and q have the meanings mentioned above,
X1 denotes a mononuclear or polynuclear aromatic radical with 6 to 30 C atoms,
and at least one phosphorus compound of the formula (I-b)
wherein the radicals R1, R2, R3 and R4, and n and q have the meanings mentioned above, and
X2 denotes a mononuclear or polynuclear aromatic radical with 6 to 30 C atoms,
with the proviso that at least one of the radicals X1, X2, R1, R2, R3 and R4 in formula (Ia) is different from its counterpart in formula (Ib).
The aromatic groups in the definition of R1, R2, R3 and R4 may be substituted independently of one another by halogen and/or alkyl groups, preferably by chlorine, bromine and/or C1-C4 alkyl. Particularly preferred aryl radicals are cresyl, phenyl, xylenyl, propylphenyl or butylphenyl, as well as the corresponding brominated and chlorinated derivatives thereof. q denotes values from 0.5 to 30, and preferably denotes an average value from 1 to 30, particularly preferably 1 to 20, especially 1 to 10. With mixtures of phosphorus compounds q may have the aforementioned average values. Monophosphorus compounds and/or oligomeric and/or polymeric phosphorus compounds may be contained in this mixture. In the case where q=0, the formula (I) describes monophosphorus compounds.
X1 and X2 are in each case preferably different and denote a mononuclear or polynuclear aromatic radical with 6 to 30 C atoms. Preferred radicals are derived from diphenols according to formula (II).
Preferred diphenols are hydroquinone, resorcinol, 4,4xe2x80x2-dihydroxydiphenyl, bis-(hydroxyphenyl)-C1-C5-alkanes, bis-(hydroxyphenyl)-C5-C6-cycloalkanes, bis-(hydroxyphenyl)-ethers, bis-(hydroxyphenyl)-sulfoxides, bis-(hydroxyphenyl)-ketones, bis-(hydroxyphenyl)-sulfones, and xcex1,xcex1-bis-(hydroxyphenyl)-diisopropylbenzenes such as their nuclear-brominated and/or nuclear-chlorinated derivatives.
Particularly preferred diphenols are 4,4xe2x80x2-diphenylphenol, bisphenol A, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 1,1-bis(4-hydroxyphenyl)-cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 4,4xe2x80x2-dihydroxydiphenyl sulfide, 4,4xe2x80x2-dihydroxydiphenyl sulfone as well as their dibrominated and tetrabrominated or chlorinated derivatives, such as for example 2,2-bis-(3-chloro-4-hydroxyphenyl)propane, 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)propane or 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)propane.
Especially preferred diphenols are bisphenol A, resorcinol, hydroquinone, dihydroxydiphenyl, and dihydroxydiphenyl sulfone.
Mixtures of phosphorus compounds of the formula (I), preferably monomeric and/or oligomeric phosphates of the formula (I), with average q values of 1 to 20, in particular 1 to 10, are particularly preferably used as component D.
Suitable as monophosphorus compounds, i.e. where q=0, are compounds such as tributyl phosphate, tris-(2-chloroethyl) phosphate, tris-(2,3-dibromopropyl) phosphate, triphenyl phosphate, tricresyl phosphate, diphenylcresyl phosphate, diphenyloctyl phosphate, diphenyl-2-ethylcresyl phosphate, tri-(isopropylphenyl)-phosphate, halogen-substituted aryl phosphates, methylphosphonic acid dimethyl ester, methylphosphonic acid diphenyl ester, phenylphosphonic acid diethyl ester, triphenylphosphine oxide or tricresylphosphine oxide.
The molding compositions according to the invention preferably contain as flame-proofing agent at least one phosphorus compound according to formula (I-c),
in which R1, R2, R3, R4, n and q have the meanings mentioned above. R5 independently denotes C1-C4 alkyl and/or halogen, k denotes 0, 1 or 2, preferably 0, and Y denotes methylene or isopropylidene.
Particularly preferably Y denotes an isopropylidene radical.
The phosphorus compounds according to component D are generally known compounds of organic chemistry and may be produced in a similar way according to known methods (see for example Ullmanns Encyklopxc3xa4die der Technischen Chemie, Vol. 18, p. 301 ff. 179; Houben-Weyl, Methoden der Organischen Chemie, Vol. 12/1, p. 43; Beistein, Vol. 6, p. 177) by using at least 2 different dihydroxy compounds, for example bisphenols or hydroquinone, for the synthesis.
Component E
The fluorinated polyolefins E are high molecular weight compounds and have glass transition temperatures of above xe2x88x9230xc2x0 C., as a rule above 100xc2x0 C., fluorine contents preferably of 65 to 76 wt. %, in particular 70 to 76 wt. %, and mean particle diameters d50 of 0.05 to 1,000 xcexcm, preferably 0.08 to 20 xcexcm. In general the fluorinated polyolefins E have a density of 1.2 to 2.3 g/cm3. Preferred fluorinated polyolefins E are polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene/hexa-fluoropropylene and ethylene/tetrafluoroethylene copolymers. The fluorinated polyolefins are known (see xe2x80x9cVinyl and Related Polymersxe2x80x9d by Schildknecht, John Wiley and Sons, Inc., New York, 1962, pp. 484-494; xe2x80x9cFluorpolymersxe2x80x9d by Wall, Wiley-Interscience, John Wiley and Sons, Inc., New York, Vol. 13, 1970, pp. 623-654; xe2x80x9cModern Plastics Encyclopediaxe2x80x9d, 1970-1971, Vol. 47, No. 10 A, October 1970, McGraw-Hill Inc., New York, pp. 134 and 774; xe2x80x9cModern Plastics Encyclopediaxe2x80x9d, 1975-1976, October 1975, Vol. 52, No. 10 A, McGraw-Hill Inc., New York, pp. 27, 28 and 472 and U.S. Pat. Nos. 3,671,487, 3,723,373 and 3,838,092) all incorporated herein by reference.
The polyolefins E may be produced according to known processes, for example by polymerising tetrafluoroethylene in an aqueous medium using a free radical-forming catalyst, for example sodium, potassium or ammonium peroxydisulfate at pressures from 7 to 71 kg/cm3 and at temperatures from 0xc2x0 to 200xc2x0 C., preferably at temperatures from 20xc2x0 to 100xc2x0 C. (For further details see for example U.S. Pat. No. 2,393,967.) Depending on the end use the density of these materials may be between 1.2 and 2.3 g/cm3, the mean particle size being between 0.5 and 1,000 xcexcm.
According to the invention preferred fluorinated polyolefins E are tetrafluoroethylene polymers having mean particle diameters of 0.05 to 20 xcexcm, preferably 0.08 to 10 xcexcm, and a density of 1.2 to 1.9 g/cm3, and are preferably used in the form of a coagulated mixture of emulsions of the tetrafluoroethylene polymers E with emulsion of the graft polymers B.
Suitable fluorinated polyolefins E that may be used in powder form are tetrafluoroethylene polymers having mean particle diameters of 100 to 1,000 xcexcm and densities of 2.0 g/cm3 to 2.3 g/cm3.
In order to produce a coagulated mixture of B and E, an aqueous emulsion (latex) of a graft polymer B is first of all mixed with a finely particulate emulsion of a fluorinated polyolefin E; suitable emulsions of fluorinated polyolefins usually have solids contents of 30 to 70 wt. %, in particular of 50 to 60 wt. %, preferably of 30 to 35 wt. %.
The quantitative details given in the description of the component B do not include the proportion of the graft polymer for the coagulated mixture of graft polymer and fluorinated polyolefins.
In the emulsion mixture the equilibrium ratio of graft polymer B to the fluorinated polyolefin E is 95:5 to 60:40. The emulsion mixture is coagulated in a known manner, for example by spray drying, freeze drying or coagulation by adding inorganic or organic salts, acids, bases or organic solvents miscible with water, such as alcohols, ketones, preferably at temperatures from 20xc2x0 to 150xc2x0 C., in particular from 50xc2x0 to 100xc2x0 C. If necessary the drying can be carried out at 50xc2x0 to 200xc2x0 C., preferably 70xc2x0 to 100xc2x0 C.
Suitable tetrafluoroethylene polymer emulsions are commercially available products and are marketed for example by DuPont as Teflon, for instance Teflon 30 N.
The compositions according to the invention may contain at least one of the conventional additives such as lubricants and mould release agents, nucleating agents, antistatics, stabilisers as well as colouring agents, pigments and/or reinforcing materials. Suitable inorganic reinforcing materials include glass fibres, optionally chopped or ground, glass beads, glass spheres, and reinforcing materials such as kaolin, talcum, mica and carbon fibres. Chopped or ground glass fibres preferably having a length of 1 to 10 mm and a diameter of  less than 20 xcexcm are preferably used as reinforcing materials in an amount of 1 to 40 parts by weight; the glass fibres are preferably surface treated.
The compositions according to the invention may furthermore contain at least one polar compound of at least one of the metals of main groups I to V or of subgroups I to VIII of the Periodic System together with at least one element selected from the group comprising oxygen, sulfur, boron, carbon, phosphorus, nitrogen, hydrogen and silicon in the form of a very finely divided inorganic powder. An oxide or hydroxide is preferably used as polar compound, preferably TiO2, SiO2, SnO2, ZnO, boehmite, ZrO2, Al2O3, iron oxides, their mixtures and doped compounds, particularly preferably boehmite or TiO2.
The compositions according to the invention may contain one or more further, optionally synergistically acting flame-proofing agents. As further flame-proofing agents of component D there may be mentioned by way of example various phosphorus compounds, organic halogenated compounds such as decabromobisphenyl ether, tetrabromobisphenol, inorganic halogenated compounds such as ammonium bromide, nitrogen compounds such as melamine, melamine-formaldehyde resins, inorganic hydroxide compounds such as Mg hydroxide, Al hydroxide, inorganic compounds such as antimony oxides, barium metaborate, hexahydroxoantimonate, zirconium oxide, zirconium hydroxide, molybdenum oxide, ammonium molybdate, zinc borate, ammonium borate and tin oxide, as well as siloxane compounds. These flame-proofing agents are generally added in an amount of up to 20 wt. % (referred to the overall molding composition).
The compositions according to the invention containing the components A to E and optionally further known additives such as stabilizers, coloring agents, pigments, lubricants and mold release agents, nucleating agents, nanoparticles as well as antistatics and reinforcing materials and flame-proofing agents are produced by mixing the respective constituents in a known manner and melt-compounding and melt-extruding the mixture at temperatures from 200xc2x0 C. to 300xc2x0 C. in conventional equipment such as internal kneaders, extruders and double-shaft screw extruders, the component E preferably being used in the form of the previously mentioned coagulated mixture.
The mixing of the individual constituents may be carried out in a known manner either successively or also simultaneously, and more specifically at about 20xc2x0 C. (room temperature) as well as at higher temperatures.
The compositions of the present invention may be used for the production of all types of molded articles. In particular molded articles may be produced by injection molding. Examples of molded articles that may be produced include all types of housing parts, e.g. for domestic appliances such as juice presses, coffee-making machines, mixers, for office equipment such as monitors, printers, copiers, or cover sheets for the building sector and parts for the automobile sector. The compositions are also used in the field of electrical engineering since they have very good electrical properties.
In addition the compositions according to the invention may be used for example to produce the following molded articles or molded parts:
internal structural parts for tracked vehicles (FR), wheelcaps, housings for electrical equipment containing small transformers, housings for equipment for information distribution and transmission, housings and covers for medical purposes, massage equipment and housings therefor, children""s toys, two-dimensional wall elements, housings for safety equipment, rear spoilers, thermally insulated transporting containers, containers for the holding or maintenance of small animals, molded parts for sanitary ware and bath fittings, cover gratings for ventilation openings, molded parts for garden sheds and equipment housings, housings for garden tools.
Further possible applications include:
in data processing equipment: telecommunications equipment such as telephones and fax machines, computers, printers, scanners, plotters, monitors, keyboards, typewriters, dictating equipment, etc.,
in electrical equipment: power supply equipment, charging devices, small transformers for computers and consumer electronics equipment, low voltage transformers, etc.,
in garden equipment: garden furniture, lawnmower housings, hoses and housings for watering devices, garden sheds, hedge trimmers, cutters, shears, spraying equipment, etc.,
in the furniture sector: work surfaces, furniture laminates, roller shutter units, office furniture, tables, chairs, seats, cupboards, shelves, door units, window units, underbed storage drawers, etc.,
in sports equipment/toys: toy vehicles, seats, pedals, sports equipment, bicycles, tables tennis tables, home gyms, golf caddies, snow boards, external parts of boats, camping equipment, picnic baskets, etc.,
for internal/external use in the building sector: house cladding/lining, profiled strips, pipework, cabling, roller shutter parts, letterboxes, lamp housings, roof tiles, paving tiles, partition walls, cable ducting, skirting boards, electrical sockets, etc.,
in the automobile/tracked vehicle sector: sidewall and roof linings, seat frames, seats, benches, tables, luggage racks, wheelcaps, rear spoilers, mudguards, rear flaps, engine bonnets, side parts, etc.
The compositions are particularly suitable for the production of molded parts in which particularly high demands are placed on the thermal stability of the plastics that are used.
A further processing variant is the production of molded articles by thermoforming previously fabricated sheets or films.
The present invention accordingly also provides for the use of the compositions according to the invention for the production of all types of molded articles, preferably those mentioned above, as well as the molded articles produced from the compositions according to the invention.

Flame-resistant and heat-resistant polycarbonate compositions

Abstract: Compositions containing:

Abstract: with the proviso that the composition contains at least 2 phosphorus compounds of the formula (I) in which X or one or more radicals R1, R2, R3 and R4 is/are different and wherein the sum of the parts by weight of the components is 100.


A valve stem seal assembly incorporates a cylindrical retainer having an axis and an upper end about which symmetrically and circumferentially arranged, alternating first and second sets of fingers have radially inwardly depending upper ends. The first set of fingers is generally parallel to the axis and the upper ends are generally perpendicular to the axis to engage a first exterior annular groove of an elastomeric seal body. The first set of fingers provides for axial attachment of the seal body to a top of a valve guide. The second set of fingers is generally arcuate and the upper ends extend radially inwardly to engage a second exterior annular groove of the seal body. The second set of fingers eliminates the need for a garter spring used by traditional valve stem seal assemblies by generating a force to urge the sealing lip against a reciprocating valve stem.

The present invention relates to a valve stem seal assemblies for use in internal combustion engines and in particular to sealing media retainers for such seal assemblies.
Those skilled in the art will appreciate the manner in which intake and exhaust valves are employed in cylinder heads of internal combustion engines. Such valves, supported for reciprocal motion within valve guides, include integral elongated valve stems extending away from the engine cylinder heads. The ends of the valve stems interact with rotating cams for cyclic repeated opening and closing of the valves against the force of valve return springs during a combustion cycle. Obviously, in order to permit unobstructed reciprocal movement of the valve stem in the valve guide, some mechanical clearance must exist between the valve guide and the moving valve stem. The valve stems thus move reciprocally to and from the cylinder head, each within its individual valve guide, and so-called valve stem seal assemblies are used to seal against leakage of oil through a clearance path between each annular engine valve guide and its associated valve stem.
Thus, as is well known, the intake port of a combustion chamber is opened and closed by the reciprocating motion of at least one intake valve, which in turn is driven by the rotary motion of a cam, the latter being affixed to and rotatable with an engine camshaft. The intake valve permits fuel mixed with air to flow into the combustion chamber. In addition, an internal combustion engine has at least one exhaust valve and associated exhaust port for releasing expended combustion gases to the atmosphere. Typically, intake and exhaust valves are of similar construction and both include valve stems integrally affixed to the valves.
In the typical engine, a valve stem seal assembly is fitted over or atop each valve guide, wherein each assembly has a retainer frictionally mounted to an associated valve guide, or is retained in place via cooperation of a return spring and a retainer flange, to assure attachment of the valve stem seal assembly within the engine. Typically each valve stem seal assembly has two primary parts; 1) an elastomeric oil seal positioned at one end to control leakage of oil between the valve stem and the valve guide, and 2) a structural cylindrical part called a retainer mounted atop of the valve guide. In many cases, the retainer has a so-called bottom flange that extends circumferentially about the bottom of the valve guide for supporting the retainer on the cylinder head deck. Additionally, traditionally manufactured elastomeric oil seals include an exterior groove for receiving a xe2x80x9cgarter springxe2x80x9d as described below.
Much progress has been achieved in the art of valve stem seal assembly design and construction. However, several design issues remain problematic for traditional valve stem seal assemblies. For example, the number of parts associated with a valve stem seal assembly has typically been the seal body and the retainer. However, a third part, called a xe2x80x9cgarter springxe2x80x9d is often disposed within a circumferential groove about the exterior of the seal body to impart a hoop stress or force to engage the seal body with the valve stem and prevent leakage of oil. The garter spring is typically made of metal and adds additional cost to the seal body assembly. An additional difficulty with traditional seal assemblies is verification of proper installation. Use of the garter spring with the retainer requires separate verification for each part. This additional verification also adds to the cost of the seal body assembly.
The inventors of the present invention have recognized these and other problems associated with traditional valve stem seal assemblies. To this end, the inventors have developed an improved valve stem seal assembly that eliminates the need for an additional garter spring while still securing a seal body to a top of a valve guide and engaging a valve stem.
Specifically, the invention is a valve stem seal assembly adapted for installation atop a valve guide of an internal combustion engine for sealingly engaging a valve stem reciprocally moveable through the valve guide. The valve stem seal assembly comprises a resilient annular seal body defining an interior annular sealing lip adapted to engage the valve stem and further including first and second exterior annular grooves. The assembly also comprises a retainer defining a generally rigid cylindrical body with upper and lower body ends and further defining an axis. Furthermore, the assembly includes a first set of fingers disposed from the lower body end to the upper body end of the retainer. The first set of fingers comprises radially inwardly depending upper ends at the upper body end of the retainer for engaging the first exterior annular groove of the seal body to maintain the seal body axially against the top surface of the valve guide. Additionally, a second set of fingers is disposed between the lower body end and the upper body end of the retainer. The second set of finger comprises radially inwardly depending upper ends for engaging the second exterior annular groove of the seal body to impart a circumferential force urging the sealing lip against of the reciprocally moveable valve stem.


A method and a network entity for controlling a service in charge of a control plane in a network are discussed. The method according to an embodiment includes receiving subscription information including an indicator related to a selected internet protocol (IP) traffic offload (SIPTO). The method further includes triggering a re-establishment of the SIPTO when a movement of a user equipment from an (e)Node B to a Home (e)Node B is detected; allowing the SIPTO excluding a SIPTO at the local network based on an access point name (APN) when the indicator indicates that the SIPTO is allowed and the SIPTO at the local network is excluded; and allowing the SIPTO including the SIPTO at the local network based on the APN when the indicator indicates that the SIPTO is allowed and the SIPTO at the local network is included.

Field of the Invention
The present invention relates to a server in charge of a control plane in a mobile communication network and a method of controlling a service, which is controlled by the server.
Discussion of the Related Art
In order to deal with many forums related to a fourth generation mobile communication and a new technology, 3GPP for establishing a technology standard of a third generation mobile communication system has started to conduct a study on LTE/SAE (Long Term Evolution/System Architecture Evolution) technology by the end of 2004 in a bid to optimize and enhance performance of 3GPP technologies.
The SAE proceeded centering on 3GPP SA WG2 is a study on a network technology having a purpose of determining a network structure in a manner of juggling an LTE job of 3GPP TSG RAN and the purpose of supporting mobility between heterogeneous networks. Currently, the SAE is one of important standardization issues of 3GPP. This is a job to develop a 3GPP system to a system supporting various radio access technologies based on an IP. The job has been progressed to achieve a target of an optimized packet-based system minimizing a transmission delay with a more enhanced data transmission capability.
An SAE upper level reference model defined by the 3GPP SA WG2 includes a non-roaming case and roaming cases of various scenarios. Detail contents may refer to 3GPP standard document TS 23.400a and TS 23.400b. A diagram of a network structure in FIG. 1 corresponds to a simple reconstruction of the SAE upper level reference model.
FIG. 1 is a diagram of a structure of an evolved mobile communication network.
One of main characteristics of the network structure in FIG. 1 corresponds that the structure is based on a 2 Tier Model, i.e., an eNode B of Evolved UTRAN and a Gateway of a Core Network. Although it is not perfectly matched to each other, it is able to say that the eNode B 20 includes the function of a Node B and an RNC of a legacy UMTS system and the Gateway includes a function of SGSN/GGSN of a legacy system.
Another main characteristic of the network structure is that a Control Plane and a User Plane between an Access network and the Core Network are exchanged by an interface different from each other. In the legacy UMTS system, there exist one interface, i.e., Iu, between RNC and SGSN. On the other hand, since an MME (Mobility Management Entity) in charge of processing a control signal has a structure separated from the GW (Gateway), two types of interface, i.e., S1-MME and S1-U, can be used, respectively. The GW can be classified into a serving gateway (hereinafter abbreviated S-GW) 52 and a packet data network gateway (hereinafter abbreviated PDN-GW or P-GW) 53.
FIG. 2 is a diagram of a relationship between an (e)Node B and a Home (e)Node B.
An attempt to increase cell capacity in order to support such a high-capacity service as multimedia content, streaming, and the like and a bidirectional service in the third generation or the fourth generation mobile communication system continues.
In particular, since various transmission techniques of high-capacity are required according to a development of a communication and dissemination of a multimedia technology, it is able to allocate more frequency resources to increase radio capacity. Yet, since the frequency resource is limited, there exist a limit for allocating the limited frequency resource to a plurality of users.
In order to increase the cell capacity, an approach of using a high frequency band and the approach of reducing a cell radius have been tried. If such a cell of a small radius as a pico cell and the like are applied, since it is able to use a frequency band higher than the frequency band used in a legacy cellular system, more information can be delivered. Yet, since more base stations are necessary to be installed in an identical area, cost may dramatically increase instead.
As mentioned in the foregoing description, recently, a femto base station such as the Home (e)Node B is proposed among the approaches of increasing the cell capacity by using a small cell.
A study on the Home (e)Node B 30 has been started to conduct centering on RAN WG3 of 3GPP Home (e)Node B. Recently, the Home (e)Node B is also studied in SA WG in earnest.
The (e)Node B 20 depicted in FIG. 2 corresponds to a macro base station and the Home (e)Node B 30 may correspond to the femto base station. It is intended that the present specification is explained based on a terminology of 3GPP and the (e)Node B is used when a Node B and an eNode B are mentioned together. And, the Home (e)Node B is used when a Home Node B and a Home eNode B are mentioned together.
Interfaces depicted with dotted lines are used for transmitting a control signal between the (e)Node B 20, the Home (e)Node B 30 and the MME 510. And, the interfaces depicted with lines are used for transmitting a data of the user plane.
FIG. 3 indicates a problem according to a prior technology.
As depicted in FIG. 3, if a traffic is overloaded or congested in the interface between the (e)Node B 20 and the S-GW 52 or if the traffic is overloaded or congested in the interface between the Home (e)Node B and the S-GW 52, a downlink data to the UE 10 or an uplink data from the UE 10 is not correctly transmitted and failed.
Or, if the interface between the S-GW 52 and the PDN-GW 53 or the interface between the PDN-GW 53 and an IP (internet protocol) service network of a mobile communication service provider is overloaded or congested, the downlink data to the UE 10 or the upload data from the UE 10 is not properly transmitted and failed.
And, when the UE performs a handover from a cell where the UE is currently receiving a service to a different cell, if the different cell is in a state of being overloaded, a service of the UE is dropped.
In order to solve the aforementioned problem, mobile communication service providers have changed the S-GW 52 and the PDN-GW 53 with a gateway of a high capacity and have built additional equipments, by which entails significantly high cost. And, since the quantity of transceived data geometrically increases, although additional equipment is newly built, it becomes overloaded soon.
Meanwhile, various methods to optimize the S-GW 52 and the PDN-GW 53 without building an additional mobile communication network have been proposed. For instance, a specific IP traffic (e.g., internet service) of the UE is transmitted in a manner of selecting an optimal path in a macro access network and the specific IP traffic is transmitted in a femto access network (e.g., Home (e)NB) in a manner of detouring in a path via nodes of a public network, i.e., a wired network without transceiving the traffic via the path of the mobile communication network. The technique making a traffic detour (Selected IP traffic offload), i.e., a SIPTO has been proposed.
FIG. 4 is a diagram of a concept of a SIPTO (Selected IP traffic offload).
Referring to FIG. 4, such a mobile communication system as an EPS (evolved packet system) is depicted as an example. The EPS system includes an (e)Node B 20, an MME 51, an S-GW 52, and a P-GW 53. And, a Home (e)Node B 30 is depicted as well.
In this case, as depicted in FIG. 4, the SIPTO (Selected IP traffic offload) technique diverts a specific IP traffic (e.g., internet service) of the UE 10 to the nodes of a wired network 70 without passing through the nodes of an IP service network 60 of a mobile communication service provider.
For instance, if the UE 10 is allowed to access the (e)Node B 20, the UE 10 generates a session, which is passing through such a wired network 70 as a public communication network, via the (e)Node B 20 and can perform an IP network service via the session. In this case, service provider policy and subscription information may be considered.
In order to generate the session, in case of the UMTS, a local gateway in charge of a part of function of GGSN or, in case the EPS, a local gateway in charge of a part of function of P-GW (PDN gateway) can be used as a gateway installed near the (e)Node B 20.
This kind of local gateway is called a local GGSN or a local P-GW. A function of the local GGSN or the local P-GW is similar to that of the GGSN or the P-GW.
As mentioned in the foregoing description, the SIPTO technique has proposed a concept of generating a session to divert (offload) the data of the UE to such a wired network as a public communication network via the (e)Node B, i.e., a macro base station.
Yet, since the aforementioned legacy SIPTO technique makes a data of a user pass through a macro base station, i.e., (e)Node B 20, if the (e)Node B 20 is in a state of being overloaded, there still exist a problem.

This patent is subject to a terminal disclaimer.

Server for control plane in mobile communication network and method for enabling the server to control service


According to the present invention there is provided a method for preparing a lithographic printing plate, the method including the steps of

The present invention relates to a heat sensitive ablatable imaging element.
More specifically the invention is related to a heat sensitive ablatable imaging element for preparing a lithographic printing plate, which requires no dissolution processing.
Lithography is the process of printing from specially prepared surfaces, some areas of which are capable of accepting lithographic ink, whereas other areas, when moistened with water, will not accept the ink. The areas which accept ink define the printing image areas and the ink-rejecting areas define the background areas.
In the art of photolithography, a photographic material is made imagewise receptive to oily or greasy inks in the photo-exposed (negative working) or in the non-exposed areas (positive working) on a hydrophilic background.
In the production of common lithographic printing plates, also called surface litho plates or planographic printing plates, a support that has affinity to water or obtains such affinity by chemical treatment is coated with a thin layer of a photosensitive composition. Coatings for that purpose include light-sensitive polymer layers containing diazo compounds, dichromate-sensitized hydrophilic colloids and a large variety of synthetic photopolymers. Particularly diazo-sensitized systems are widely used.
Upon imagewise exposure of the light-sensitive layer the exposed image areas become insoluble and the unexposed areas remain soluble. The plate is then developed with a suitable liquid to remove the diazonium salt or diazo resin in the unexposed areas.
Alternatively, printing plates are known that include a photosensitive coating that upon image-wise exposure is rendered soluble at the exposed areas. Subsequent development then removes the exposed areas. A typical example of such photosensitive coating is a quinone-diazide based coating.
Typically, the above-described photographic materials from which the printing plates are made are exposed in contact through a photographic film that contains the image that is to be reproduced in a lithographic printing process. Such method of working is cumbersome and labor intensive. However, on the other hand, the printing plates thus obtained are of superior lithographic quality.
Attempts have thus been made to eliminate the need for a photographic film in the above process and in particular to obtain a printing plate directly from computer data representing the image to be reproduced. However the above mentioned photosensitive coatings are not sensitive enough to be directly exposed to a laser. Therefor it has been proposed to coat a silver halide layer on top of the photosensitive coating. The silver halide can then directly be exposed by means of a laser under the control of a computer. Subsequently, the silver halide layer is developed leaving a silver image on top of the photosensitive coating. That silver image then serves as a mask in an overall exposure of the photosensitive coating. After the overall exposure the silver image is removed and the photosensitive coating is developed. Such method is disclosed in for example JP-A- 60- 61 752 but has the disadvantage that a complex development and associated developing liquids are needed.
GB- 1 492 070 discloses a method wherein a metal layer or a layer containing carbon black is provided on a photosensitive coating. This metal layer is then ablated by means of a laser so that an image mask on the photosensitive layer is obtained. The photosensitive layer is then overall exposed by UV-light through the image mask. After removal of the image mask, the photosensitive layer is developed to obtain a printing plate. This method however still has the disadvantage that the image mask has to be removed prior to development of the photosensitive layer by a cumbersome processing.
Furthermore methods are known for making printing plates involving the use of imaging elements that are heat-sensitive rather than photosensitive. A particular disadvantage of photosensitive imaging elements such as described above for making a printing plate is that they have to be shielded from the light. Furthermore they have a problem of sensitivity in view of the storage stability and they show a lower dot crispness. The trend towards heat mode printing plate precursors is clearly seen on the market.
EP-A- 444 786, JP- 63-208036, and JP- 63-274592 disclose photopolymer resists that are sensitized to the near IR. So far, none has proved commercially viable and all require wet development to wash off the unexposed regions. EP-A- 514 145 describes a laser addressed plate in which heat generated by the laser exposure causes particles in the plate coating to melt and coalescence and hence change their solubility characteristics. Once again, wet development is required.
U.S. Pat. No. 5,605,780 discloses a lithographic printing plate comprising an anodized aluminum support and an image-forming layer overlying said support; said image-forming layer comprising an IR absorbing agent dispersed in a film-forming polymeric binder; said film-forming polymeric binder being a cyanoacrylate polymer and said IR-absorbing agent being dispersed therein in an amount sufficient for said image-forming layer to be imaged by laser-induced thermal ablation which completely removes said image forming layer in exposed regions thereof to thereby reveal said underlying support. This method has the disadvantage that in said way it is very difficult to generate a fog-free aluminum support. Plates made by ablation can not be printed without scumming.
EP-A- 652 483 discloses a lithographic printing plate requiring no dissolution processing which comprises a substrate bearing a heat-sensitive coating comprising a photothermal converter, which coating becomes relatively more hydrophilic under the action of heat. This principle has as disadvantage that the lithographic latitude is very narrow whereby pretty fast toning occurs at the exposed areas.
It is an object of the invention to provide an ablative imaging element for preparing a lithographic printing plate requiring no dissolution processing which is positive working.
It is also an object of the invention to provide an ablative imaging element for preparing a lithographic printing plate requiring no dissolution processing which shows a good ink-uptake in the exposed areas and no toning in the non-exposed areas.
According to the present invention there is provided a method for preparing a lithographic printing plate, said method comprising the steps of
(1) providing an imaging element comprising on a lithographic hydrophilic support as contiguous top layer a heat-sensitive coating comprising a compound capable of converting light to heat and a compound, which becomes more hydrophilic under the action of heat;
(2) imagewise exposing said imaging heat-sensitive composition with a high intensity laser emitting a laser beam with an intensity at the surface of said heat-sensitive composition of at least 2 mW/xcexcm2 thereby at least partially removing said heat-sensitive composition to expose at least partially the lithographic support.
The top layer, being the heat-sensitive or image-forming layer which becomes more hydrophilic under the influence of heat comprises a switchable binder and a compound capable of transferring light into heat. A switchable binder is a polymer or copolymer which under-the influence of heat and/or acid undergoes a polarity transfer from hydrophilic to hydrophobic or vice versa. According to the present invention a switchable binder is used which becomes more hydrophilic by heating and/or under the influence of acid. By xe2x80x9cmore hydrophilicxe2x80x9d is meant an increase in the wettability of the coating by aqueous solutions of substantially neutral pH (i. e. in the pH range of 4 to 10), the coating retaining its structural integrity. Increased wettability is evidenced by a decrease in the contact angle formed between the coating and the aqueous solution. This surface polarity difference is sufficient to prepare a classical offset printing plate. However, the lithographic latitude is restricted.
Preferably the switchable binders according to the invention are polymers or copolymers which contain pendant polar functions, capable of reacting under the action of heat and/or acid to form more polar, hydrophilic groups. Examples of groups which behave in this way include t-alkylcarboxylates, e.g. t-butylesters, as disclosed in EP-A- 249139, t-alkyl carbonates e.g. t-butyl carbonates, as disclosed in polymer bulletin, 17, 1-6 (1987), benzyl carboxylates e.g. nitrobenzyl or cyanobenzyl esters as disclosed in U.S. Pat. No. 4,963,463, and dimethyl benzyl esters as disclosed in Polym. Mat. Sci. Eng. 1989, 60, 142, and alkoxyalkyl esters, as disclosed in WO 92/09934. The latter are preferred, and may be represented by the formula (I)
in which:
one of R1 or R2 is hydrogen and the other is hydrogen or an alkyl group up to 18 carbon atoms,
R3 represents an alkyl group up to 18 carbon atoms; or any two of R1,
R2 and R3 may together form a carbocyclic or heterocyclic ring, and
T represents a divalent linking group bonded to a polymer backbone
Further details regarding suitable identities for T and the polymer backbone are disclosed in WO 92/09934.
Preferably, R1 is hydrogen and R2 and R3 together complete a 5- or 6-membered ring.
Preferably the polymer is derived from tetrahydropyranyl methacrylate (THPM) and has repeat units of formula (II)
The cyclic acetal ester groups in the units of formula (II) are relatively hydrophobic and are stable at ambient temperatures under neutral or alkaline conditions. At elevated temperatures, a cleavage reaction is believed to take place, generating the corresponding carboxylic acid which is polar and hydrophylic.
The process is greatly enhanced by the presence of acid, and enables the production of a lithographic printing surface without the need of dissolution development, since image-wise generation of heat and/or acid within the coating of a relevant polymer produces a corresponding pattern of hydrophilic (ink-repellent) and hydrophobic (ink-accepting) areas on the imaging element.
The properties of the reactive polymer may be enhanced by blending with other polymers, as disclosed in WO 92/09934. Polymers and copolymers of maleic anhydride are particularly suitable for this purpose, and may comprise up to 90 wt % of the coating, but preferably not more than 50 wt %. the resulting blends show improved durability and enhanced differential in wettability.
The reactive polymer may comprise repeating units derived from one or more comonomers that do not contain heat-sensitive groups. For example, THPM (or a similar monomer) may be copolymerized with any of the conventional acrylate or methacrylate or other vinyl monomers to produce polymers with varying physical properties, provided said comonomer do not contain strongly acidic groups (such as carboxylic acid, sulphonic acid etc.) which may cause unwanted cleavage of the reactive groups. Preferred comonomers include vinyl-functional trialkoxysilanes, such as methacryloyloxypropyltrimethoxysilane (MPTS), in quantities of up to 50 mol % of the reactive polymer. The preferred copolymer comprises 90 mol % THPM and 10 mol % MPTS.
The image forming layer may comprise more than one switchable polymer although that is not preferred.
The image-forming layer includes a compound capable of converting light into heat. Suitable compounds capable of converting light into heat are preferably infrared absorbing components although the wavelength of absorption is not of particular importance as long as the absorption of the compound used is in the wavelength range of the light source used for image-wise exposure. Particularly useful compounds are for example dyes and in particular infrared absorbing dyes and pigments and in particular infrared absorbing pigments. Examples of infrared absorbing dyes are disclosed in EP-A- 97 203 131.4. Examples of infrared absorbing pigments are carbon black, metal carbides, borides, nitrides, carbonitrides, bronze-structured oxides and oxides structurally related to the bronze family but lacking the A component e.g. WO2.9. It is also possible to use conductive polymer dispersion such as polypyrrole or polyaniline-based conductive polymer dispersions. Said compound capable of converting light into heat is preferably present in the top layer but can also be included in an underlying layer.
Said compound capable of converting light into heat is present in the imaging element preferably in an amount between 1 and 25% by weight of the total weight of the image forming layer, more preferably in an amount between 2 and 20% by weight of the total weight of the image forming layer. The compound capable of converting light into heat is most preferably present in the imaging element in an amount to provide an optical density at a wavelenght between 800 nm and 1100 nm of at least 0.35.
Optionally, the image-forming layer comprises a thermal acid. The term xe2x80x9cthermal acidxe2x80x9d relates to a non-acid compound, which release an acid by heating.
Ionic thermal acids are suitable for use in this invention. Examples of these include onium salts, in particular iodonium, sulfonium, phosphonium, selenonium, diazonium and arsonium salts.
Useful ionic thermal acids include those represented by the formula:
X+R1R2R3R4 Wxe2x88x92
When X is iodine then R3 and R4 are electron lone pairs and R1 and R2 each independently are aryl or substituted aryl groups. When X is S or Se then R4 is an electron lone pair and R1, R2 and R3 each independently can be an aryl group, a substituted aryl group, an aliphatic group or a substituted aliphatic group. When X is P or As, then R1, R2, R3 and R4 each independently can be an aryl group, a substituted aryl group, an aliphatic group or a substituted aliphatic group. W can be BF4, CF3SO3, SbF6, CCl3CO2, ClO4, AsF6, PF6, or any corresponding acid whose pKa is less than three.
Any of the onium salts described in U.S. Pat. No. 4,708,925 can be utilized as the thermal acid in this invention. These include iodonium, sulfonium, phosphonium, bromonium, chloronium, oxysulfoxonium, oxysulfonium, sulfoxonium, selenonium, telluronium and arsonium salts.
Use of diazonium salts as a thermal acid is particularly preferred in this invention.
Specific examples of particularly useful onium salts include
diphenyliodonium hexafluorophosphate,
triphenylsulfonium hexafluoroantimonate,
phenylmethyl-ortho-cyanobenzylsulfonium trifluoromethane sulfonate, and
2-methoxy-4-aminophenyl diazonium hexafluorophosphate
Non-ionic thermal acids are also suitable for use in this invention. Examples of these include compounds of the formula
RCH2X, RCHX2, RCX3, R(CH2X)2 and R(CH2X)3
wherein X is Cl, Br, F, or CF3SO3 and R is an aromatic group or an aliphatic group.
Further suitable non-ionic thermal acids are haloalkyl-substituted s-triazines as disclosed in EP-A- 672 954, o-quinone diazides, photo acid generating agents having an o-nitrobenzyl type protective group as described in Polymer Sci., by S. Hayase et al, 25, 573 (1987); the compounds which are subjected to a photodecomposition to generate a sulfonic acid, represented by iminosulfonates as described in Polymer Preprints Japan, by M. Tunooka et al, 35 (8), by disulfon compounds described in JP-Pi 61-166544, by a-sulphonyloxy ketones, by a-hydroxymethylbenzoine sulphonates, by nitrobenzyl sulphonates, by a-sulphonyl acetophenones and by sulphonyl imides, the preparation of these last compounds being well known in the literature; the compounds which are subjected to a photodecomposition to generate a phosphonic acid, a partly esterified phosphoric acid or phosphoric acid, represented by nitrobenzylphosphates or phosphonates as described in Tetrahedron Letters, by M. Rubinstein et al., 17, 1445 (1975), by benzoine phosphates or phosphonates, as described in J. Org. Chem. by M. Pirrung and S. Shuey, 59 , 3890 (1994), by pyrenemethylphosphates or phosphonates, by iminophosphates or phosphonates and by imidophosphates or phosphonates, the preparation of these last compounds being well known in the literature.
Further, compounds in which the above thermal acids are introduced into a primary chain or a side chain of a polymer can be used. Examples thereof include the compounds described in e.g. J.Am.Chem.Soc., by M. E. Woodhouse et al, 104, 5586 (1982); J.Imaging Sci., by S. P. Pappas et al, 30 (5), 218 (1986); etc.
Furthermore this IR-sensitive layer is preferably a visible light- and UV-light desensitized layer. This preferably visible light- or UV-light desensitized layer does not comprise photosensitive ingredients such as diazo compounds, photoacids, photoinitiators, quinone diazides, sensitisers etc. which absorb in the wavelength range of 250 nm to 650 nm. In this way a daylight stable printing plate can be obtained.
The image-forming layer is preferably applied in an amount between 0.1 and 10 g/m2, more preferably in an amount between 0.5 and 5 g/m2.
The hydrophilic lithographic support may be as well a rigid as a flexible support
In the imaging element according to the present invention, the support can be an anodized aluminum. A particularly preferred support is an electrochemically grained and anodized aluminum support
According to another embodiment in connection with the present invention, said hydrophilic lithographic base can be a hardened hydrophilic layer, containing a hydrophilic binder and a hardening agent coated on a flexible support.
Such hydrophilic binders are disclosed in e.g. EP-A- 450 199, which therefor is incorporated herein by reference. Preferred hardened hydrophilic layers comprise partially modified dextrans or pullulan hardened with an aldehyde as disclosed in e.g. EP-A- 514 990 which therefor is incorporated herein by reference. More preferred hydrophilic layers are, layers of polyvinyl alcohol hardened with a tetraalkyl orthosilicate and preferably containing SiO2 and/or TiO2 wherein the weight ratio between said polyvinylalcohol and said tetraalkyl orthosilicate is between 0.5 and 5 as disclosed in e.g. GB-P- 1 419 512, FR-P- 2 300 354, U.S. Pat. No. 3,971,660, U.S. Pat. No. 4,284,705, EP-A- 405 016 and EP-A- 450 199 which therefor are incorporated herein by reference.
Flexible supports may be opaque or transparent, e.g. a paper support or resin support. When a paper support is used preference is given to one coated at one or both sides with an Alpha-olefin polymer. It is also possible to use an organic resin support e.g. poly(ethylene terephthalate) film or poly-Alpha-olefin films. The thickness of such organic resin film is preferably comprised between 0.07 and 0.35 mm. These organic resin supports are preferably coated with a hydrophilic adhesion layer which can contain water insoluble particles such as silica or titanium dioxide.
The imaging element can be prepared by applying the different layers according to any known technique. Alternatively said imaging element may be prepared on the press with the support already on the press by a coater placed in the immediate vicinity of the press.
Imaging in connection with the present invention can be done by an image-wise scanning exposure involving the use of a laser or a LED, more preferably of a laser or a LED that operates in the infrared or near-infrared, i.e. wavelength range of 700-1500 nm. Most preferred are laser diodes emitting in the near infrared. Exposure of the imaging element can be performed with lasers with a short as well as with lasers with a long pixel dwell time. Preferred are lasers with a pixel dwell time between 0.005 xcexcs and 20 xcexcs.
The intensity of the laser or LED at the surface of said heat-sensitive composition is at least 2 mW/xcexcm2, more preferably at least 4 mW/xcexcm2 in order to ablate at the exposed areas the heat sensitive composition that is not ablated, has become hydrophilic so that said residue is not detrimental to the hydrophilicity of the exposed areas and does not sause scum.
After the exposure the imaging element is ready to be used as a lithographic printing plate.
In another embodiment of the invention the exposure of the imaging element can be carried out with the imaging element already on the press. A computer or other information source supplies graphics and textual information to a laser or a LED via a lead.
The printing plate of the present invention can also be used in the printing process as a seamless sleeve printing plate. This cylindrical printing plate which has as diameter the diameter of the print cylinder is slided on the print cylinder instead of applying in a classical way a classically formed printing plate. More details on sleeves are given in xe2x80x9cGrafisch Nieuwsxe2x80x9d ed. Keesing, 15, 1995, page 4 to 6.

Method for preparing a lithographic printing plate by ablation of a heat sensitive ablatable imaging element

Abstract: (1) providing an imaging element including on a lithographic hydrophilic support as contiguous top layer a heat-sensitive coating including a compound capable of converting light to heat and a compound, which becomes more hydrophilic under the action of heat;

Abstract: (2) imagewise exposing the imaging heat-sensitive composition with a high intensity laser emitting a laser beam with an intensity at the surface of the heat-sensitive composition of tat least 2 mW/xcexcm2 thereby at least partially removing the heat-sensitive composition to expose at least partially the lithographic support.


An inexpensive bullet-shaped plug is shown for use in a blasting hole containing water in the bottom thereof, which plug permits dry powder to be used above the waterline rather than more expensive wet powder. After the blasting holes are drilled, if water accumulates in the bottom thereof, the bullet-shaped plug with a center weight is dropped into the hole, which bullet-shaped plug floats on the water. Small rocks are dropped on top of the bullet-shaped plug causing upper tentacles to flare out to engage the wall of the blasting hole. Dry powder is then loaded into the blasting hole on top of the bullet-shaped plug. A cap is inserted a distance below the surface of the blasting hole. Thereafter, a series of similar blasting holes are blown at one time to create debris that can be removed or further processed.

1. Technical Field
An explosive powder plug and method of using same is shown and, more particularly, an explosive powder plug that can be used in blasting holes having water in the bottom thereof so that dry blasting powder can be used in the blasting hole.
2. Background of the Invention
When digging into the earth's surface, hard objects such as rocks, ore, coal or other hard objects are encountered. A typical way of removing the hard object is to drill a series of boreholes (also called blasting holes) along a blast line, fill the borehole with blasting powder and blow the holes. Thereafter, the loose debris may either be removed or further processed as desired.
The problem is that many of the blasting holes drilled along the blast line may accumulate some water in the bottom thereof. The current trend in the blasting industry is if there is any water in the bottom of the blasting hole to use a wet blasting powder the entire length of the blasting hole. This is not cost efficient because wet blasting powder costs three to four times the amount of dry blasting powder.
The probability of water accumulating in the blasting hole is less in the more arid regions, but increases significantly as the rainfall for the area increases. In many blasting holes, there is only a small accumulation of water in the bottom thereof, yet wet blasting powder would be used for blowing the holes because of the water accumulation. This is especially true in mining, road construction and utility installations. Some practical way is needed so that dry powder can be used in a blasting hole that only has a small amount of water accumulated in the bottom thereof.

Explosive powder plug and method of using the same


A cutting tool includes a working member power coupled to a power drive arrangement held by a housing. The housing includes a front housing portion from which the working member protrudes and a rear housing portion. A first handle includes a first hand-grip portion adapted for a user to hold the power tool at an operative level above the ground level, a second handle adapted for a user to generate a turning moment about the first handle so as to vary inclination of the working member relative to the ground level. The second handle includes a movable hand-grip portion which is attached to the rear housing portion. The rear housing portion is pivotally connected to the front housing portion, and the movable hand-grip portion of the second handle is arranged to pivotally move the rear housing portion relative to the front housing portion.

Hand-held power tools are widely used both in industries and at homes. Commonly known hand-held power tools include chain saws, hedge trimmers, drills (e.g., electric or pneumatic), power wrench (e.g., electric or pneumatic), saws and the like.
Such hand-held power tools are usually quite heavy and typically comprise a handle for holding the power tool at an operating level which is above the ground. When a power tool is held in a normal operating which is above the ground, a power coupled movable part, for example, a cutting blade or a drill bit, will protrude away from a user for engaging with an object distal from a user. The vertical operating levels of a power tool can vary significantly according to specific or instantaneous modes of applications. For example, a power tool may need to be held near the ground level or to be held well above the head of a user for overhead applications, for example, for trimming tall trees or for drilling holes on high walls.
A power tool is usually quite heavy and is usually ergonomically designed for use at a particular operation level above the ground level. A user always finds it very uncomfortable, and sometimes even awkward, to use a power tool at an operating level away from the operating level for which the power tool is ergonomically designed. Typically, such a level is usually very high or very low relative to the height of a user. The discomfort would become especially apparent and unbearable when a user has to operate the power tool for a more extended period of time, for example, for more than 20-30 minutes or even hours. Therefore, it will be highly desirable if there can be provided power tools which would mitigate the discomfort due to conventional designs of power tools as mentioned above.


The invention provides compositions and methods of use thereof for labeling peptide and proteins in vitro or in vivo. The methods described herein employ lipoic acid ligase or mutants thereof, and lipoic acid analogs recognized by lipoic acid ligase and lipoic acid ligase mutants.

Biophysical probes such as fluorophores, spin labels, and photoaffinity tags have greatly improved the understanding of protein structure and function in vitro, and there is great interest in using them inside cells to study proteins within their native context. The major bottleneck to using such probes inside cells, however, is the difficulty of targeting the probes with very high specificity to particular proteins of interest, given the chemical heterogeneity of the cell interior. The most prominent method for labeling cellular proteins is to genetically encode green fluorescent protein (GFP) or one of its variants as a fusion to the protein of interest. Because GFPs are genetically encoded, their labeling is absolutely specific and GFP variants have proven extremely useful for in vivo studies of protein localization, however, they still have severe limitations such as their large size (˜235 amino acids), which can perturb the function of the protein of interest, and the fact that they are not very bright and only amenable to optical microscopy. For example, the best of the previously described methods, the FlAsH labeling method uses an extremely small tetracysteine motif to direct a biarsenical-containing probe. This method has yielded exciting new biological information, but suffers from poor specificity, and cell toxicity. Most other methods such as the SNAP/AGT, Halotag, DHFR, FKBP(12), and single-chain antibody methods use protein rather than peptide-based targeting sequences, raising concerns about steric interference with receptor function. Peptide-based targeting methods include FlAsH, His6-tag labeling, phosphopantetheinyl transferase labeling, transglutaminase labeling, and keto/biotin ligase labeling. His6 labeling and FlAsH suffer from probe dissociation, whereas ketone/biotin lipase and transglutaminase are restricted to labeling at the cell surface.

Methods and compositions for protein labeling using lipoic acid ligases