The present invention relates to a method for direct diagnosis and treatment of a patient with a pain of muscular origin. The method comprises: a) applying an electric stimulus to a muscle in a suspected area of pain, using a neuromuscular stimulator; b) recording the patient""s response to the stimulus; c) repeating steps a) and b) in a different area with resultant decrease in discomfort; d) repeating a), b) and c) to find a point of maximal sensitivity; and e) effectively treating the point of maximum sensitivity.

1. CROSS-REFERENCE TO RELATED APPLICATION . . . 2
2. BACKGROUND OF THE INVENTION . . . 2
2.1. Field of the Invention . . . 2
2.2. Description of the Background Art . . . 3
3. SUMMARY OF THE INVENTION . . . 4
4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS . . . 5
4.1 Description . . . 5
4.2. Example . . . 8
5. CLAIMS . . . 11
6. ABSTRACT . . . 12
2.1. Field of the Invention
The present invention relates to a method of determining the cause of pain in a patient and then provide a specific treatment for such pain. More particularly, the present invention relates to a method of determining whether the pain is originated from the muscles of the patient and provide a specific treatment for such pain. More particularly, the present invention relates to a method of electrical stimulation which can accurately pinpoint the specific area of a muscle producing a patient""s pain complaint.
2.2. Description of the Background Art
Myofascial pain syndrome can be literally interpreted to describe pain coming from muscles and connective tissue. Despite its liberal meaning in various literature, myofascial pain syndrome normally refers to a wide variety of supposed clinical entities, such as tension, weakness, stiffness, trigger points and tender points. In addition, myofascial pain syndrome can be part of the syndrome referred to as fibromyalgia.
Among the most common causes of pain seen in clinical practice, myofascial pain syndrome is characterized by myofascial trigger points. Trigger points are only one of the many causes that have been equated with myofascial pain. Even though there is no clinical procedure/criteria as to examining patients with muscle pain, many clinicians consider myofascial trigger points as tender areas of muscle that have associated point tenderness on a taught muscle band, local twitch response, referred pain, reproduction of usual pain, restricted range of motion, weakness without atrophy, and autonomic symptoms. Other clinicians believe that pain on palpation reproducing the usual pain is enough to make the diagnosis of a trigger point.
Satellite myofascial trigger points often develop in the zone of referred pain. Secondary myofascial trigger points are found in muscles in the functional motor unit affected. Once these satellite or secondary myofascial trigger points develop, they may persist, eventually referring pain to their own pain reference zones. In this way, the areas of the body involved with myofascial pain syndrome increases, eventually affecting multiple regions.
It is essential for the proper diagnosis and treatment of myofascial pain syndrome that all of the etiologies associated with pain caused by muscle and connective tissue be identified. The prior art has required skill by the clinician in the physical examination of muscle in finding the specific point in the muscle causing the pain in order to identify myofascial trigger points. Since criteria vary for the diagnosis of trigger points, interrater reliability in locating myofascial trigger points is frequently low
Accuracy, consistency, stability and reproducibility of the examination technique is referred to as reliability. The agreement between two or more examiners is referred to as interrater reliability. Interrater reliability is poor when palpation is used as the identifying technique, in part due to the lack of standards as to the amount of pressure to exert when palpating a muscle.
The prior art attempts to locate or confirm myofascial trigger points using techniques more objective than palpation. Such techniques include a palpation index, handheld pressure threshold meter, electronic pressure meter attached to the fingers, thermographic measurement of heat emission and electromyographic identification.
However, these techniques are difficult to learn and use on routine patients in a limited period of time. A simple method is desired that can accurately define, diagnose and lead to the treatment of all of the causes of muscle pain, including trigger points associated with the patient""s pain complaint.
Accordingly, it is an object of the present invention to provide a method for diagnosing myofascial pain syndrome with precision to enable more effective treatment of the condition.
Another object of the invention is to provide a technique for examining a patient having myofascial pain syndrome with better accuracy, consistency, stability and reproducibility of the procedure.
Yet another object is to provide a method of examining a patient having myofascial pain syndrome with a high degree of interrater reliability in locating trigger points.
Yet another object is to provide a technique for diagnosing myofascial pain syndrome in the specific area of the muscle producing pain complaint within a limited period of time.
Yet another object is to provide a diagnosis that offers a possible explanation for pain which without such diagnosis would automatically be attributed to the spine and nervous system, possibly leading to utilization of expensive and unnecessary tests and treatments including surgery.
These and other objects of the invention as well as other advantages thereof can be apprehended by reference to the following description and claims.
The foregoing objects are achieved according to the present invention which provides a simple method by which the physician can accurately define, diagnose, and treat specific muscle causes of a patient""s pain complaint. In a preferred embodiment, electrical stimulation is used to find muscle pain emanating from trigger points.
According to a preferred embodiment of the present invention, the method comprises: (a) applying an electric stimulus to a muscle through a neuromuscular stimulator and recording the patient""s response; (b) repeating step (a) in a different location with resultant decrease in discomfort; and (c) effectively treating the points of maximum sensitivity.
The method of the present invention is useful for all patients whose muscles may be the underlying cause of the pain complaint. It is particularly useful when trigger points are considered in very muscular and/or obese patients since manual palpation of these patients will frequently produce a low pressure in deep muscles. Such a low pressure is insufficient to excite a painful area in order to produce discomfort and thus prove the muscles to be causes of the patient""s pain.
The present invention is useful in the treatment of pain for a variety of conditions, and in particular back pain, neck pain, shoulder pain, extremity pain, headaches, and abdominal pain.
4.1 Description
A. Initial Evaluation
The process begins with an initial evaluation. The initial evaluation should produce details of a patient""s activities and habits that may cause the pain. The initial evaluation is an important part of the entire diagnosis, since the ultimate goal is to eliminate factors that cause the pain. After a successful treatment is conducted, these factors would be eliminated from the patient""s repertoire.
Types of such factors would be all activities involved in over-use or inappropriate use of musculature. Such inappropriate use would include the following situations: (1) engaging in athletic activities with insufficient warm-up or exercising machines that produce non-physiological positioning, (2) exercising with machines that produce unbalanced exercise routines or abrupt changes in the intensity of an exercise machine, such as changes in the use of an exercise equipment like a re-stringed a tennis racquet, (3) engaging in work position that could lead to strain of muscle groups, such as typing on a computer keyboard placed on the top of a desk rather than in a tray under the desk, looking at a computer monitor improperly positioned so that it is not directly in front of the patient and at eye level or slightly below, holding a telephone handset to the user""s ear, or reading and watching television in bed. Hence, no matter what the patient""s occupation or use of leisure time is, one can always discover other activities that produce repetitive strain to muscles.
The pain complaint is detailed as much as possible to determine frequently found patterns of pain involving specific muscle groups. For example, a back pain radiating down the leg is frequently thought of as coming from nerve root compression beginning in the spine. In most cases this will not be so. Therefore, whenever a pain pattern would traditionally suggest compression of nerves in the spine, one should be thinking of the typical muscle patterns that could also be producing the same symptom complex. Muscle pain will frequently be made worse by inactivity and relieved to some degree with motion of the effected muscles. The effected muscle may not produce pain when the patient only engages in minimal activity; but as soon as a greater intensity of activity is initiated, the pain may recur.
The physical examination is critical for the diagnosis of muscle pain. The examination will determine if the patient has minimal trunk muscle strength and flexibility to support themselves without discomfort. The basic test is the Kraus-Weber test, originally developed at Columbia University in the 50""s. The Kraus-Weber test measures strength of abdominal muscles and hip flexors as well as back muscle extensors. It measures the flexibility of the low back, hamstrings, and calf muscles as well. The test provides us with a measure of trunk muscle tension, weakness, and stiffness. These diagnoses are all amiable to correction with Kraus"" exercise program developed at Columbia University in 1954. After the Kraus-Weber test, the patient is manually examined.
The first part of the manual examination is pinching the skin in the painful area. The skin in the painful area will itself be painful in more than 50% of patients presenting with muscle pain. One should moderately forcefully pinch the patient, grabbing approximately 2 cm of skin between the thumb and forefinger, and then comparing the discomfort in that region with skin over the midriff as a reference point. When the skin is very tender, this tenderness can be eliminated with a skin rolling massage, which is a pinching, kneading, rolling massage to the area of the painful skin. These massages are given every other day and last for 15 minutes each time. They are very uncomfortable and the patient is iced to the painful skin area for approximately 8 minutes prior to the skin rolling massage. Following eight sessions of such massages, in almost all cases the skin pain is dramatically reduced or eliminated. The patient is then instructed to use a loofa sponge on the previously painful skin area in a bath or shower on a daily basis.
Muscles are then examined. The muscles are firmly palpated, comparing right to left whenever the examination is done to see if there is a significant difference between the right side and left side. This examination may demonstrate that the patient has diffuse tenderness or focal tenderness. When there is focal tenderness it may be the result of stiffness, tension, spasm or trigger points. Spraying a coolant spray such as ethyl chloride onto the muscle and asking the patient to contract and relax the muscle rhythmically for 1 or 2 minutes and spraying in between whenever the patient reports continued pain may eliminate the pain coming from tension and stiffness. It may temporarily help a muscle in spasm; but it will not relieve a trigger point.
The Marcus method states that trigger points do not develop for approximately 2 months after the initiation of pain in a particular region of the body. If a patient is treated early enough with techniques to be described below, the pain may disappear.
A confounding element in the prior art is, when one determines that a trigger point is present and if such diagnosis is made, the technique to treat the diagnosed point area or muscle. The techniques currently considered community standard, accept without question repeated injection of a muscle for weeks, months, or years. The technique of injecting that we utilize is based on the assumption that the entire muscle is dysfunctional and therefore, that when a trigger point is found, the entire muscle needs to be injected along the entire origin and insertion of that particular muscle. Because this requires extensive injecting, only one muscle is done per day. Deciding on the presence of the trigger point remains a clinical challenge.
B. Direct Diagnosis
Our unique contribution is our discovery that high voltage electrical stimulation of a suspected area will pinpoint of the muscles involved in causing the patient""s pain. In the present invention, an electrical stimulus is applied to a muscle through neuromuscular stimulator. The stimulus is applied through a roving electrode that can be moved over a painful muscle until the patient reports discomfort. The electrode is then moved to another area with resultant decrease in discomfort. This process is repeated to ascertain the accuracy of the point of maximal sensitivity. Preferably the process is repeated 2 to 10 times, and preferably 3 to 4 times. This produces a reliable replication of the patient""s pain and gives the treating physician the security that an injection is warranted.
With repeated stimulation to the muscle that is painful, should one find that the patient reports a decrease in pain with subsequent stimulation, then this is the area that in most cases will not require injection but will respond to additional electrical stimulation coupled with deep point massage. The uniqueness of the present invention, however, is the ability to find the spot that does not yield to electricity but consistently produces the patient""s pain. No other technique in the prior art describes such a diagnostic capacity. This, coupled with the unique approach of injecting the entirety of the muscle rather than a specific point, makes this technique dramatically more effective as a diagnostic and treating regime for common pain problems such as low back pain.
Should this technique be used in its entirety, the generic term myofascial pain syndrome would become a manageable entity since specific treatments for specific aspects the syndrome could and would be applied. Since the diagnosis and treatment of muscles as a primary cause of pain heretofore was absent, patients have suffered physically, emotionally and financially by overlooking inexpensive effective techniques and utilizing inappropriate, ineffective diagnostics and treatment techniques.

Method for direct diagnosis and treatment of pain of muscular origin


The subject invention relates to a foundry binder system which cures in the presence of a volatile amine curing catalyst comprising (a) an epoxy resin, (b) an acrylated organic polyisocyanate, (c) a reactive unsaturated acrylic monomer, acrylic polymer, or mixtures thereof, and (d) an oxidizing agent comprising a hydroperoxide. The foundry binders are used for making foundry mixes. The foundry mixes are used to make foundry shapes which are used to make metal castings.

The subject invention relates to a foundry binder system which cures in the presence of a volatile amine curing catalyst comprising (a) an epoxy resin, (b) an acrylated organic polyisocyanate, (c) a reactive unsaturated acrylic monomer, acrylic polymer, or mixtures thereof, and (d) an oxidizing agent comprising a hydroperoxide. The foundry binders are used for making foundry mixes. The foundry mixes are used to make foundry shapes which are used to make metal castings.
One of the major processes used in the foundry industry for making metal parts is sand casting. In sand casting, disposable foundry shapes (usually characterized as molds and cores) are made by shaping and curing a foundry mix which is a mixture of sand and an organic or inorganic binder. The binder is used to strengthen the molds and cores.
The two major processes used in sand casting for making molds and cores are the (a) cold-box process and the (b) no-bake process. In the cold-box process, a gaseous curing agent is passed through a compacted shaped mix to produce a cured mold and/or core. In the no-bake process, a liquid curing catalyst is mixed with the sand and shaped into a core or and/or mold.
The major cold-box process is based upon polyurethane-forming binders. See for example U.S. Pat. Nos. 3,409,579 and 3,676,392. These systems are cured with a gaseous tertiary amine catalyst. The polyurethane-forming binder system usually consists of a phenolic resin component and polyisocyanate component which are mixed with sand prior to compacting and curing to form a foundry mix.
When the two components of the polyurethane-forming binder system are mixed with the sand to form a foundry mix, they may prematurely react prior to curing with the gaseous catalyst. If this reaction occurs, it will reduce the flowability of the foundry mix when it is used for making molds and cores, and the resulting molds and cores will have reduced strengths. This reduced flowability and decrease in strength with time is related to the benchlife of the foundry mix.
Sufficient benchlife of the foundry mix is important to the commercial success of these binders. Benchlife is the time interval between forming the foundry mix and the time when the foundry mix is no longer useful for making acceptable molds and cores. A measure of the usefulness of the foundry mix and the acceptability of the molds and cores prepared with the foundry mix is the tensile strength of the molds and cores. If a foundry mix is used after the benchlife has expired, the resulting molds and cores will have unacceptable tensile strengths.
Because it is not always possible to use the foundry mix immediately after mixing, it is desirable to prepare foundry mixes with an extended benchlife. When polyurethane-forming cold-box binders are used, generally a compound which improves the benchlife of the foundry mix must be added to the binder, usually to the polyisocyanate component of the binder.
Among the compounds useful for extending the benchlife of the foundry mix are organic and/or inorganic phosphorus containing compounds. Examples of organic phosphorus-containing compounds used as benchlife extenders with polyurethane-forming binder systems are disclosed in U.S. Pat. No. 4,436,881 which discloses certain organic phosphorus containing compounds such as dichloroarylphosphine, chlorodiarylphosphine, arylphosphinic dichloride, or diarylphosphinyl chloride, and U.S. Pat. No. 4,683,252 which discloses organohalophosphates such as mono-phenyldichlorophosphate.
Examples of inorganic phosphorus-containing compounds which extend the benchlife of polyurethane-forming binder systems are disclosed in U.S. Pat. No. 4,540,724 which discloses inorganic phosphorus halides such as phosphorus oxychloride, phosphorus trichloride, and phosphorus pentachloride, and U.S. Pat. No. 4,602,069 which discloses inorganic phosphorus acids such as orthophosphoric acid, phosphoric acid, hypophosphoric acid, metaphosphoric acid, pyrophosphoric acid, and poly-phosphoric acid.
As can be seen, there are numerous benchlife extenders for polyurethane-forming cold-box binders which reflects the interest in extending the benchlife of the foundry mix.
Despite the cited work, there is still a need for amine-cured binder systems with longer benchlife, particularly those which do not require expensive additives.
The invention relates to a foundry binder system which will cure in the presence of a volatile amine curing catalyst comprising:
(a) from 5 to 80 weight percent of an epoxy resin;
(b) from 10 to 80 weight percent of an acrylated organic polyisocyanate;
(c) from 5 to 75 weight percent of a reactive unsaturated acrylic monomer, acrylic polymer, and mixtures thereof; and
(d) an effective oxidizing amount of an oxidizing agent comprising a hydroperoxide,
where (a), (b), (c), and (d) are separate components or can be mixed with another component, provided (b) or (c) is not mixed with (d), and where said weight percents are based upon the total weight of (a), (b), (c), and (d). Generally, the weight percent of (a) is 5 to 50, the weight percent of (b) is 10 to 40, the weight percent of (c) is 20 to 60 and the weight percent of (d) is 1 to 30. Preferably, the weight percent of (a) is 5 to 20, the weight percent of (b) is 15 to 40, the weight percent of (c) is 20 to 55, and the weight percent of (d) is 1 to 20. More preferably, the weight percent of (a) is 5 to 25, the weight percent of (b) is 20 to 40, the weight percent of (c) is 30 to 55, and the weight percent of (d) is 5 to 15.
The foundry binders are used for making foundry mixes. The foundry mixes are used to make foundry shapes which are used to make metal castings. The use of an acrylated organic polyisocyanate in the foundry binder instead of an organic polyisocyanate which is not acrylated, improves the benchlife of foundry mixes made with the foundry binder. The foundry mixes produce cores and molds with adequate tensile strengths for commercial use. Castings, made with an assembly of cores and/or molds made with the binders, are acceptable for commercial use. Additionally, the binder does not contain any free phenol or free formaldehyde, and has zero or low volatile organic compounds (VOC).
It is preferred to package and use the binders system as a two part system. Part I (epoxy component) comprises the epoxy resin, oxidizing agent, solvents, and other optional components. Part II (polyisocyanate component) comprises the (1) acrylated organic polyisocyanate, (2) a reactive unsaturated acrylic monomer, polymer, or mixtures thereof, (3) solvents, and (4) other optional components. Usually, the Part I is first mixed with sand and then the Part II is added to make a foundry mix which is shaped and cured. The weight ratio of epoxy resin to acrylated organic polyisocyanate generally is from 1:10 to 10:1, preferably from 1:5 to 5:1, most preferably from 1:3 to 3:1. The weight ratio of acrylated polyisocyanate to reactive unsaturated acrylate is generally from 1:10 to 5:1, preferably from 1:5 to 2:1.
For purposes of this disclosure, xe2x80x9cepoxy resinxe2x80x9d is defined as a thermosetting resin which contains one or more reactive epoxide group per molecule. Such resins have either a mixed aliphatic-aromatic or exclusively non-aromatic (i.e., aliphatic or cycloaliphatic) molecular structure. The mixed aliphatic-aromatic epoxy resins generally are prepared by the well-known reaction of a bis-(hydroxy-aromatic)alkane or a tetrakis-(hydroxy-aromatic) alkane with a halogen-substituted aliphatic epoxide in the presence of a base such as sodium hydroxide or potassium hydroxide. Examples of the halogen-substituted aliphatic epoxides include epichlorohydrin, 4-chloro-1 ,2-epoxybutane, 5-bromo-1,2-epoxypentane, 6-chloro-1,3-epoxyhexane and the like. In general, it is preferred to use a chloride substitute terminal denoting that the epoxide group is on the end of the alkyl chain.
The most widely used epoxy resins are diglycidyl ethers of bisphenol A. These are made by reaction of epichlorohydrin with bisphenol A in the presence of an alkaline catalyst. By controlling the operating conditions and varying the ratio epichlorohydrin to bisphenol A, products of different molecular weight can be made. Other epoxy resins include (a) the diglycidyl ethers of other bisphenol compounds such as bisphenol B, F, G, and H, (b) epoxy resins produced by reacting a novolac resin with a halogen-substituted aliphatic epoxide such as epichlorohydrin, 4-chloro- 1,2-epoxybutane, 5-bromo- 1,2-epoxypentane, 6-chloro-1,3-epoxyhexane and the like, (c) epoxidized polybutadiene resins, and (d) epoxidized drying oils.
Particularly preferred are epoxy resins with a weight per epoxy group of 175 to 200. Although the viscosities of the epoxy resins are high, usually greater than 5,000 cps at 25xc2x0 C., the epoxy component viscosity is reduced to a workable level when the epoxy resin is mixed with the oxidizing agent. Useful epoxy resins are disclosed in U.S. Pat. No. 4,518,723 which is hereby incorporated by reference into this disclosure.
The oxidizing agent used in the Part I includes at least one hydroperoxide, and may also include ketone peroxides, peroxy ester oxidizing agents, alkyl oxides, chlorates, perchlorates, and perbenzoates. Preferably, however, the oxidizing agent is a hydroperoxide or a mixture of peroxide and hydroperoxide. Hydroperoxides particularly preferred in the invention include t-butyl hydroperoxide, cumene hydroperoxide, paramenthane hydroperoxide, etc. The organic peroxides may be aromatic or alkyl peroxides. Examples of useful diacyl peroxides include benzoyl peroxide, lauroyl peroxide and decanoyl peroxide. Examples of alkyl peroxides include dicumyl peroxide and di-t-butyl peroxide. Mixtures of one or more of the above organic peroxides or hydroperoxides can be utilized.
Although not necessarily preferred, the epoxy component, may contain a solvent, such as an aromatic hydrocarbon solvent such as benzene, toluene, xylene, ethylbenzene, naphthalenes, or an ester solvent, such as rapeseed methyl ester, or mixtures thereof, and the like. If a solvent is used, sufficient solvent should be used so that the resulting viscosity of the Part I is less than 1,000 centipoise, preferably less than 400 centipoise. Generally, however, the total amount of solvent is used in an amount of 0 to 25 weight percent based upon the total weight of the epoxy resin.
For the purpose of defining this invention, xe2x80x9can acrylated organic polyisocyanatexe2x80x9d is an organic polyisocyanate which is reacted with a hydroxyl or carboxylic acid containing unsaturated acrylic monomer, acrylic polymer, or mixtures thereof. The term xe2x80x9cacrylated organic polyisocyanatexe2x80x9d includes mixtures of acrylated organic polyisocyanates and organic polyisocyanates which are not acrylated and have free isocyanato groups (NCO groups). The acrylated organic polyisocyanate may be a totally acrylated organic polyisocyanate, where all of the NCO groups of the organic polyisocyanate are reacted with the hydroxyl or carboxylic acid group of the unsaturated acrylic monomer or polymer; or preferably a partially acrylated organic polyisocyanate which contains free NCO groups after the reaction.
The acrylated organic polyisocyanate must contain some free NCO, which is either found in the molecules of the partially acrylated organic polyisocyanate and/or in organic polyisocyanates having free NCO which are mixed with the acrylated organic polyisocyanate. Although any acrylated organic polyisocyanate can be blended with an organic polyisocyanate, it is necessary to blend totally acrylated organic polyisocyanates with an organic polyisocyanate having free NCO, since the totally acrylated organic polyisocyanates do not have free NCO groups. Typically the amount of organic polyisocyanate blended with the acrylated organic polyisocyanate is from 0 to about 98 weight, based upon the combined weight of the acrylated organic polyisocyanate and the organic polyisocyanate blended with it, preferably from 2 to 98 weight percent. The acrylated polyisocyanate (which includes blends of acrylated organic polyisocyanates, whether they be totally or partially acrylated, and organic polyisocyanates which are not acrylated), typically contains at least 5 weight percent free NCO and typically no more than 20 weight percent free NCO, where the weight percent is based upon the weight of the binder system, preferably from 7 weight percent to 11 weight percent free NCO.
The acrylated organic polyisocyanate is prepared by reacting the organic polyisocyanate with typically from 2 to 49 weight percent, preferably from 2 to 30 weight percent, of a reactive unsaturated acrylic monomer or polymer having a free hydroxyl or free carboxylic acid functional group. Typical acrylic monomers, which can be used as the reactive unsaturated acrylic monomer in preparing the acrylated organic polyisocyanates, include hydroxyalkyl acrylates, carboxylic acid containing acrylates, alkoxyalkyl acrylates, hydroxyalkyl methacrylates, alkoxyalkyl methacrylates, N-alkoxymethylacrylamides, N-alkoxymethylmethacrylamides, and mixtures thereof. Preferably used as the monomers to modify the organic polyisocyanate are acrylic monomers selected from the group consisting of acrylic acid, methacrylic acid, substituted variations of acrylic acid or methacrylic acid, hydroxy ethyl acrylate, and hydroxy propyl acrylate.
Typical acrylic polymers, which can be used as the reactive unsaturated polymer to prepare the acrylated organic polyisocyanates, include epoxy acrylate reaction products, polyester/urethane/acrylate reaction products, acrylated urethane oligomers, polyether acrylates, polyester acrylates, acrylated epoxy resins, vinyl polyesters, vinyl esters, and dicylopentadiene resins.
The general procedure for preparing the acrylated organic polyisocyanate involves heating the acrylic monomer or polymer in the presence of the organic polyisocyanate until all of the hydroxy or carboxylic acid component has reacted.
The organic polyisocyanate used to prepare the partially acrylated organic polyisocyanate is an organic polyisocyanate having a functionality of two or more, preferably 2 to 5. It may be aliphatic, cycloaliphatic, aromatic, or a hybrid polyisocyanate. Mixtures of such polyisocyanates may be used. Representative examples of organic polyisocyanates are aliphatic polyisocyanates such as hexamethylene diisocyanate, alicyclic polyisocyanates such as 4,4xe2x80x2-dicyclohexylmethane diisocyanate, and aromatic polyisocyanates such as 2,4-diphenylmethane diisocyanate and 2,6-toluene diisocyanate, and dimethyl derivatives thereof. Other examples of suitable organic polyisocyanates are 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, xylylene diisocyanate, and the methyl derivatives thereof, polymethylenepolyphenyl isocyanates, chlorophenylene-2,4-diisocyanate, and the like. The organic polyisocyanate is used in a liquid form. Solid or viscous polyisocyanates must be used in the form of organic solvent solutions, the solvent generally being present in a range of up to 80 percent by weight of the solution.
The reactive unsaturated acrylic monomer, polymer, or mixture thereof, preferably as part of the Part II, contains ethylenically unsaturated bonds, but does not contain any free hydroxyl or carboxylic acid functional groups. Examples of such materials include a wide variety of monofunctional, difunctional, trifunctional, tetrafunctional and pentafunctional monomeric acrylates. A representative listing of these monomers includes alkyl acrylates, acrylated epoxy resins, cyanoalkyl acrylates, alkyl methacrylates, cyanoalkyl methacrylates, and difunctional monomeric acrylates. Other acrylates which can be used include trimethylolpropane triacrylate, methacrylic acid and 2-ethylhexyl methacrylate.
Typical reactive unsaturated acrylic polymers, which may also be used include epoxy acrylate reaction products, polyester/urethane/acrylate reaction products, acrylated urethane oligomers, polyether acrylates, polyester acrylates, and acrylated epoxy resins.
Although solvents are not required for the organic polyisocyanate component, typical solvents which can be used are generally polar solvents include liquid dialkyl esters such as dialkyl phthalate of the type disclosed in U.S. Patent 3,905,934 and other dialkyl esters such as dimethyl glutarate. Methyl esters of fatty acids, particularly rapeseed methyl ester, are also useful solvents. Suitable aromatic solvents are benzene, toluene, xylene, ethylbenzene, and mixtures thereof. Preferred aromatic solvents are mixed solvents that have an aromatic content of at least 90% and a boiling point range of 138xc2x0 C. to 232xc2x0 C. Suitable aliphatic solvents include kerosene.
Free radical scavengers or inhibitors. such as benzoquinone can be added to the binder. Benzoquinone acts as a free radical inhibitor/scavenger to inhibit the free radical reactions that cause instability in the binder. The amount of benzoquinone used is generally from 0 to 3 weight percent, preferably 0 to 1 weight percent based upon the total weight of the binder. The benzoquinone may be incorporated into a solvent which may be used in either the epoxy component (Part I) or the polyisocyanate component (Part I), or both. It is especially beneficial when used in the part containing the reactive unsaturated acrylic monomer or polymer.
Various types of aggregate and amounts of binder are used to prepare foundry mixes by methods well known in the art. Ordinary shapes, shapes for precision casting, and refractory shapes can be prepared by using the binder systems and proper aggregate. The amount of binder and the type of aggregate used is known to those skilled in the art. The preferred aggregate employed for preparing foundry mixes is sand wherein at least about 70 weight percent, and preferably at least about 85 weight percent, of the sand is silica. Other suitable aggregate materials for ordinary foundry shapes include zircon, olivine, aluminosilicate, chromite sands, and the like.
In ordinary sand type foundry applications, the amount of binder is generally no greater than about 10% by weight and frequently within the range of about 0.5% to about 7% by weight based upon the weight of the aggregate. Most often, the binder content for ordinary sand foundry shapes ranges from about 0.6% to about 5% by weight based upon the weight of the aggregate in ordinary sand-type foundry shapes.
It will be apparent to those skilled in the art that other additives such as silanes, silicones, benchlife extenders, release agents, defoamers, wetting agents, etc. can be added to the aggregate, or foundry mix. The particular additives chosen will depend upon the specific purposes of the formulator.

Foundry binder of epoxy resin, acrylated polyisocyanate and acrylic


The present invention relates to an improved structure for a steel door which comprises a steel door frame and a steel door panel which is hinged on one side of the steel door frame, wherein the steel door panel comprises a steel-made door panel frame and a door opening defined by the door panel frame, the door opening has an interior portion which is disposed with a plurality of steel guarding members forming graphics, portions other than the guarding members in the door opening form hollowed units; a rear side of the door panel frame is disposed with a glass door panel which corresponds with the door opening, the glass door panel comprises a steel-made glass door panel frame which surrounds a peripheral body of the door opening and is formed on the rear side of the door panel frame, and a glass which is embedded in the glass door panel frame, one side of the glass door panel frame is hinged on one side of the door panel frame, the glass door panel frame is completely hidden behind the rear side of the door panel frame. The structure enables the entire content of the graphics formed by the plurality of members viewable from either the front side or the rear side of the steel door, thereby bringing about better visual effect on the graphical presentation and enhancing the artistic and ornamental quality of the steel door.

The present invention relates to an improved structure for a steel door and more particularly pertains to an improved structure for an indoor steel door.
There are many varieties of structures of indoor steel doors. Among which, the structure of a steel door comprises a steel door frame and a steel door panel (101) which is hinged on one side of the steel door frame. The steel door panel (101) comprises a steel-made door panel frame (102) and a door opening (103) defined by the door panel frame. The door opening (103) has an interior portion which is disposed with a plurality of members (104) forming graphics, portions other than the graphics in the door opening form hollowed units (105). The rear side of the door panel frame is disposed with a glass door panel (106) which corresponds with the door opening. The glass door panel (106) comprises a glass door panel frame (107) which surrounds a peripheral body of the door opening and is formed on the rear side of the door panel frame, and a glass (108) which is embedded in the glass door panel frame. One side of the glass door panel frame is hinged on one side of the door panel frame. A large portion of the glass door panel frame extends into the door opening (103), resulting in a large portion of the graphics formed by the plurality of the members (104) overlapping with the glass door panel frame as viewed from either the front side or the rear side. In other words, the glass door panel frame blocks out parts of the graphics, thereby seriously affecting the visual effect of the graphical presentation, and substantially diminishing the artistic and ornamental quality of the steel door. Besides, when the glass door is required to be opened for ventilation, the steel door in the prior art is not able to prevent mosquitoes, pests or other things from flying into a house from outside, thereby seriously affecting household living environment and body health.


A process for the preparation of pulverulent, cationic, crosslinked polymers based on monoethylenically unsaturated monomers containing a quaternized or quaternizable nitrogen atom comprises carrying out the polymerization in supercritical carbon dioxide as inert diluent with mixing at from 31xc2x0 C. to 150xc2x0 C. and above 73 bar.

The present invention relates to a process for the preparation of pulverulent, cationic, crosslinked polymers based on monoethylenically unsaturated monomers containing a quaternized or quaternizable nitrogen atom, by free-radical polymerization in supercritical carbon dioxide.
It is known in general terms that supercritical carbon dioxide can be used as solvent in the preparation of polymers by free-radical polymerization. For example, EP-A 220 603 describes a process for the preparation of uncrosslinked, pulverulent polymers based on N-vinyl monomers and/or ethylenically unsaturated carboxylic esters by free-radical polymerization in supercritical carbon dioxide. EP-A 239 035 describes the preparation of crosslinked, pulverulent polymers based on monoethylenically unsaturated carboxylic acids, or amides and/or esters thereof by polymerization in supercritical carbon dioxide. In the known processes, the reaction mixture and liquid carbon dioxide are generally introduced into a pressure vessel, and the supercritical state induced by increasing the temperature and pressure. However, it is disadvantageous here that the different solubilities of the monomers and crosslinking agents in the solvent means that products of nonuniform morphology or nonuniform chemical composition may be formed.
It is an object of the present invention to find an improved process for the preparation of crosslinked polymers.
We have found that this object is achieved by a process for the preparation of pulverulent, cationic, crosslinked polymers based on monoethylenically unsaturated monomers containing a quaternized or quaternizable nitrogen atom by free-radical-initiated polymerization, which comprises carrying out the polymerization in supercritical carbon dioxide as inert diluent with mixing at from 31xc2x0 C. to 150xc2x0 C. and above 73 bar.
The polymerization is carried out under pressure in supercritical carbon dioxide as inert diluent. The properties of carbon dioxide in the liquid and supercritical states have been reported by J. A. Hyatt, J. Org. Chem. 49, (1984), 5097-5101. According to this article, the critical point of carbon dioxide is at about 31xc2x0 C. and 73 bar. The polymerization is preferably carried out under pressure in supercritical carbon dioxide at above about 31xc2x0 C., the critical temperature of carbon dioxide. The upper temperature limit for the preparation of the polymers is 10xc2x0 C. above the commencement of this softening range of the respective polymers formed. For most polymers, the upper value for this temperature limit is 150xc2x0 C. The polymerization is preferably carried out at from 30 to 130xc2x0 C. The reaction temperature need not be kept constant; it is also possible to set up a stepped or ramped temperature profile. It is advisable to set the temperatures at the beginning of the reaction to values in the range from 31 to 100xc2x0 C. The pressures are above 73 bar, preferably in the range from 80 to 300 bar, particularly preferably from 120 to 250 bar.
The novel process is preferably carried out by firstly introducing carbon dioxide in the solid, liquid or gaseous state into the reaction space of a pressure apparatus which is conventional per se, then converting the carbon dioxide into the supercritical state by increasing the pressure to above 73 bar and the temperature to above 31xc2x0 C., then setting the reaction temperature, and subsequently metering in the starting materials. The starting materials, such as monomers, free-radical initiators, crosslinking agents and, if desired, polymerization regulators, may be metered in individually or in the form of mixtures. Thus, it may be advisable, for example, to dissolve the free-radical initiators in the monomers. The procedure selected depends essentially on the solubilities of the individual components in one another and in the diluent. However, it is also possible to introduce all or some of the starting materials into the reaction space and then to add the carbon dioxide. If desired, starting materials can be metered in during the reaction (semibatch procedure).
The polymerization reaction is initiated with the aid of polymerization initiators which decompose to form free radicals. It is possible to use all initiators which are known for the polymerization of the monomers, for example initiators which decompose to form free radicals with half-value periods of less than 3 hours at the selected temperature. If the polymerization is carried out at different temperatures by starting the polymerization of the monomers at a low temperature and completing the polymerization at a significantly higher temperature, it is advantageous to use at least two different initiators which have an adequate decomposition rate in the temperature range selected in each case.
Based on 100 parts by weight of the monomer mixture, from 100 to 3000 parts by weight, preferably from 200 to 1500 parts by weight, of carbon dioxide are used. The carbon dioxide is preferably anhydrous. The polymerization reaction can be carried out batchwise or continuously with mixing of the reactants in pressure apparatuses of appropriate design. In order to dissipate the heat formed during the polymerization, it is desirable for the pressure apparatuses to have a cooling system. They must of course also be heatable in order to heat the reaction mixture to the respective temperature desired for the polymerization. The pressure apparatuses should have mixing means, for example stirrers (blade, impeller, multistage pulsed countercurrent or ribbon stirrers) or vanes.
The novel process is particularly suitable for the preparation of pulverulent, cationic, crosslinked polymers.
These pulverulent, cationic, crosslinked polymers are obtainable by free-radical-initiated polymerization of
(a1) from 1 to 99.99% by weight of a free-radical-polymerizable monomer containing a quaternized or quaternizable nitrogen atom, or a mixture of such monomers,
(a2) from 5 to 95% by weight of an N-vinyllactam,
(b) from 0.01 to 20% by weight of a monomer which effects crosslinking, and
(c) from 0 to 50% by weight of a further free-radical-copolymerizable monomer.
Suitable monomers (a1) are selected from one of the following groups:
N-vinylimidazole derivatives of the formula (I)
in which R1, R2 and R3, independently of one another, are hydrogen, C1-C4-alkyl or phenyl, preferably 2-methyl-N-vinylimidazole or N-vinylimidazole;
N,N-diallylamines of the formula (II),
in which R4 is a C1-C24-alkyl radical, preferably N,N-diallyl -N-methylamine.
Under the polymerization conditions in accordance with the invention, such diallylamines react with ring closure:
N,N-dialkylaminoalkyl derivatives of acrylic or methacrylic acid, of the formula (III)
in which R5 and R6, independently of one another, are hydrogen or methyl, Z is a nitrogen atom where X=0, R7 is a linear or branched C1-C24-alkylene radical, and R8 and R9, independently of one another, are C1-C24-alkyl radicals.
Suitable monomers of the formula (III) are, for example, N,N-dimethylaminomethyl (meth)acrylate, N,N-diethylaminomethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminobutyl (meth)acrylate, N,N-diethylaminobutyl (meth)acrylate, N,N-dimethylaminohexyl (meth)acrylate, N,N-dimethylaminooctyl (meth)acrylate, N,N-dimethylaminododecyl (meth)acrylate, N-[3-(dimethylamino)propyl]acrylamide, N-[3-(dimethylamino)butyl]methacrylamide, N-[8-(dimethylamino)octyl]methacrylamide, N-[12-(dimethylamino)dodecyl]-methacrylamide, N-[3-(diethylamino)propyl]methacrylamide and N-[3-(diethylamino)propyl]acrylamide, and mixtures thereof.
Preferred monomers (a1) are 3-methyl-1-vinylimidazolium chloride and methosulfate, dimethyldiallylammonium chloride, and N,N-dimethylaminoethylmethacrylate and N-[3-(dimethylamino)propyl]methacrylamide, each of which has, if desired, been quaternized by methyl chloride, dimethyl sulfate or diethyl sulfate.
Particularly preferred monomers (a1) are 3-methyl-1-vinylimidazolium chloride and methosulfate and dimethyldiallylammonium chloride; very particularly preferred monomers (a1) are 3-methyl-1-vinylimidazolium chloride and methosulfate.
It is also possible to use mixtures of the monomers (a1).
Preferably, from 5 to 70% by weight, particularly preferably from 10 to 50% by weight, of the monomers (a1) are employed.
The monomers (a1) can either be used as monomers in quaternized form or polymerized in unquaternized form; in the latter case, the resultant copolymer is either quaternized or protonated. If the monomers are used in quaternized form, they can be employed either as dried substances or in the form of concentrated solutions in solvents which are suitable for the monomers, for example in polar solvents, such as water, methanol, ethanol, acetone or electrolyte solutions.
The protonation can be carried out, for example, using mineral acids, such as HC1, H2SO4, or monocarboxylic acids, for example formic acid or acetic acid, dicarboxylic acids or polybasic carboxylic acids, for example oxalic acid or citric acid, or any other proton-releasing compounds or substances which are capable of protonating the corresponding nitrogen atom. Water-soluble acids are particularly suitable for protonation.
The protonation of the polymer can be carried out either after the polymerization or during formulation of the cosmetic preparation, during which a physiologically compatible pH is generally established.
The term protonation is taken to mean at least some of the protonatable groups of the polymer, preferably from 20 to 100%, are protonated, resulting in a cationic overall charge of the polymer.
The quaternization of the compounds of the formulae (I) to (III) is carried out, for example, using alkyl halides having 1 to 24 carbon atoms in the alkyl group, for example methyl chloride, methyl bromide, methyl iodide, ethyl chloride, ethyl bromide, propyl chloride, hexyl chloride, dodecyl chloride, lauryl chloride or benzyl halide, in particular benzyl chloride or benzyl bromide. Other suitable quaternizing agents are dialkyl sulfates, in particular dimethyl sulfate or diethyl sulfate. The quaternization of the basic monomers of the formulae (I) to (III) can also be carried out using alkylene oxides, such as ethylene oxide or propylene oxide, in the presence of acids.
The quaternization of the monomers or of a polymer using one of said quaternizing agents can be carried out by methods which are known in general terms.
Preferred quaternizing agents are methyl chloride, dimethyl sulfate and diethyl sulfate.
Suitable monomers (a2) are N-vinyllactams, for example N-vinylpiperidone, N-vinylpyrrolidone and N-vinylcaprolactam, preferably N-vinylpyrrolidone.
Suitable crosslinking agents (monomers (b)) are, for example, acrylates, methacrylates, allyl ethers and vinyl ethers of at least dihydric alcohols. Some or all of the OH groups of the parent alcohols may have been etherified or esterified; however, the crosslinking agents contain at least two ethylenically unsaturated groups.
Examples of parent alcohols are dihydric alcohols, such as 1,2-ethanediol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, but-2-ene-1,4-diol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,5-hexanediol, 1,10-decanediol, 1,2-dodecanediol, 1,12-dodecanediol, neopentyl glycol, 3-methylpentane-1,5-diol, 2,5-dodecanediol, 1,12-dodecanediol, neopentyl glycol, 3-methylpentane-1,5-diol, 2,5-dimethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,4-bis(hydroxymethyl)cyclohexane, neopentyl glycol hydroxypivalate, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis[4-(2-hydroxypropyl)phenyl]propane, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, 3-thiopentane-1,5-diol, and polyethylene glycols, polypropylene glycols and polytetrahydrofurans having molecular weights of from 200 to 10,000. Besides the homopolymers of ethylene oxide or propylene oxide, it is also possible to use block copolymers of ethylene oxide or propylene oxide or copolymers containing incorporated ethylene oxide or propylene oxide groups. Examples of parent alcohols having more than two OH groups are trimethylolpropane, glycerol, pentaerythritol, 1,2,5-pentanetriol, 1,2,6-hexanetriol, triethoxycyanuric acid, sorbitan, sugars, such as sucrose, glucose and mannose. It is of course also possible to use the polyhydric alcohols in the form of corresponding ethoxylates or propoxylates after reaction with ethylene oxide or propylene oxide. The polyhydric alcohols can also first be converted into the corresponding glycidyl ethers by reaction with epichlorohydrin.
Other suitable crosslinking agents are the vinyl esters or the esters of monohydric, unsaturated alcohols with ethylenically unsaturated C3-C6-carboxylic acids, for example acrylic acid, methacrylic acid, itaconic acid, maleic acid or fumaric acid. Examples of such alcohols are allyl alcohol, 1-buten-3-ol, 5-hexen-1-ol, 1-octen-3-ol, 9-decen-1-ol, dicyclopentenyl alcohol, 10-undecen-1-ol, cinnamyl alcohol, citronellol, crotyl alcohol or cis-9-octadecen-1-ol. However, it is also possible to esterify the monohydric, unsaturated alcohols using polybasic carboxylic acids, for example malonic acid, tartaric acid, trimellitic acid, phthalic acid, terephthalic acid, citric acid or succinic acid.
The crosslinking agents used can also be esters of unsaturated carboxylic acids with the polyhydric alcohols described above, for example oleic acid, crotonic acid, cinnamic acid or 10-undecenoic acid.
Also suitable are straight-chain or branched, linear or cyclic, aliphatic or aromatic hydrocarbons having at least two double bonds, which, in the case of aliphatic hydrocarbons, must not be conjugated, for example divinylbenzene, divinyltoluene, 1,7-octadiene, 1,9-decadiene, 4-vinyl-1-cyclohexene, trivinylcyclohexane or polybutadienes having molecular weights of from 200 to 20,000.
Other suitable crosslinking agents are acrylamides, methacrylamides and N-allylamines of at least difunctional amines. Examples of such amines are 1,2-diaminomethane, 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, 1,12-dodecanediamine, piperazine, diethylenetriamine or isophoronediamine. Also suitable are the amides made from allylamine and unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, itaconic acid, maleic acid or at least dibasic carboxylic acid as described above.
Furthermore, triallylamine and triallylmonoalkylammonium salts, for example triallylmethylammonium chloride or methylsulfate, are suitable as crosslinking agents.
Also suitable are N-vinyl compounds of urea derivatives, at least difunctional amides, cyanurates or urethanes, for example of urea, ethyleneurea, propyleneurea or tartaramide, for example N,Nxe2x80x2-divinylethyleneurea or N,Nxe2x80x2-divinylpropyleneurea.
Also suitable are alkylenebisacrylamides, such as methylenebisacrylamide and 1,1xe2x80x2-bis (2,2xe2x80x2- and 1,1xe2x80x2-bis(3,3xe2x80x2-vinylbenzimidazol-2-one)-1,4-butane
Examples of other suitable crosslinking agents are alkylene glycol di(meth)acrylates, such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, vinyl acrylate, allyl acrylate, allyl methacrylate, divinyl dioxane, pentaerythritol triallyl ether and mixtures of these crosslinking agents.
Other suitable crosslinking agents are tetraallylsilane and tetravinylsilane.
Examples of particularly preferred crosslinking agents are methylenebisacrylamide, triallylamine and triallylalkylammonium salts, divinylimidazole, N,Nxe2x80x2-divinylethyleneurea, products of the reaction of polyhydric alcohols with acrylic acid or methacrylic acid, methacrylic esters and acrylic esters of polyalkylene oxides or polyhydric alcohols which have been reacted with ethylene oxide and/or propylene oxide and/or epichlorohydrin. Very particularly preferred crosslinking agents are methylenebisacrylamide, N,Nxe2x80x2-divinylethyleneurea and acrylic esters of glycol, butanediol, trimethylolpropane or glycerol or acrylic esters of glycol, butanediol, trimethylolpropane or glycerol of the reaction with ethylene oxide and/or epichlorohydrin.
The crosslinking agent is especially soluble in the reaction medium. If the solubility of the crosslinking agent in the reaction medium is low, it can be dissolved in a monomer or monomer mixture or alternatively metered in dissolved in a solvent which is miscible with the reaction medium. Particular preference is given to crosslinking agents which are soluble in the monomer mixture.
The content of crosslinking agent may affect the solution viscosity of the novel polymers to a great extent.
The further, free-radical-polymerizable monomers (c) may be the following: N-vinylacetamide, N-methyl-N-vinylacetamide, acrylamide, methacrylamide, N,N-dimethylacrylamide, N-methylolmethacrylamide, N-vinylformamide, N-vinyloxazolidone and N-vinyltriazole. The group of monomers (c) includes, for example, acrylonitrile, methacrylonitrile, acrylic and methacrylic esters derived from monohydric C1- to C18-alcohols, hydroxy-C2- to C4-alkylesters of acrylic acid and methacrylic acid, maleic anhydride, vinyl esters, 2-acrylamido-2-methylpropanesulfonic acid and/or vinylphosphoric acid. Also suitable are esters of acrylic acid and methacrylic acid with fatty alcohol ethoxylates and fatty alcohol propoxylates in which the fatty alcohol component has 10 to 20 carbon atoms and the ethylene oxide or propylene oxide content is from 1 to 20 mol %. Such alcohol components are obtained, for example, by reacting C10- to C20-fatty alcohols with ethylene oxide and/or propylene oxide and esterifying the resultant alkoxylated fatty alcohols using acrylic acid or methacrylic acid. The use of these comonomers gives crosslinked copolymers which have high electrolyte resistance. The monomers from group (c) are used in an amount of from 0 to 30% by weight, preferably up to 15% by weight. If they are used for the modification of the copolymers from (a) and (b), the lower limit is 5% by weight, based on the monomer mixture. The total of the percentages for monomers (a), (b) and (c) is in all cases 100%. Examples of esters of acrylic acid and methacrylic acid are methyl acrylate, ethyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, stearyl acrylate, stearyl methacrylate and the acrylic esters of the isomeric butyl alcohols. Suitable hydroxy-C2- to C4-alkyl esters of acrylic acid and methacrylic acid are, for example, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxybutyl methacrylate. Of the vinyl esters, preference is given to vinyl acetate and vinyl propionate. Other suitable monomers are olefins, such as ethylene or propylene, styrene and alkylethylene glycol acrylates and ethacrylates having 1 to 50 ethylene glycol units.
Suitable initiators for the free-radical polymerization are ater-soluble and water-insoluble peroxo and/or azo compounds, or example alkali metal or ammonium peroxydisulfates, hydrogen peroxide, dibenzoyl peroxide, tert-butyl perpivalate, 2,2xe2x80x2-azobis(2,4-dimethylvaleronitrile), tert-butyl peroxyneodecanoates, tert-butyl per-2-ethylhexanoate, di-tert-butyl peroxide, tert-butyl hydroperoxide, azobisisobutyronitrile, azobis(2-amidinopropane) dihydrochloride and 2,2xe2x80x2-azobis(2-methylbutyronitrile). Also suitable are initiator mixtures or redox initiator systems, for example ascorbic acid/iron(II) sulfate/sodium peroxodisulfate, tert-butyl hydroperoxide/sodium disulfite, and tert-butyl hydroperoxide/sodium hydroxymethanesulfonate. The initiators can be used in the conventional amounts, for example from 0.05 to 7% by weight, based on the amount of the monomers to be polymerized.
The concomitant use of redox coinitiators, for example benzoin, dimethylaniline and complexes and salts of heavy metals, such as copper, cobalt, manganese, nickel and chromium and in particular iron, which are soluble in organic solvents allows the half-value periods of said peroxides, in particular the hydroperoxides, to be reduced, so that, for example, tert-butyl hydroperoxide is effective even at 100xc2x0 C. in the presence of 5 ppm of copper(II) acetylacetonate.
Preference is given to sparingly water-soluble or water-insoluble initiators.
The polymerization can, if desired, also be carried out in the presence of polymerization regulators in order to regulate the molecular weight of the polymers. If it is desired to prepare particularly low-molecular-weight copolymers, larger amounts of polymerization regulators are used, while the preparation of high-molecular-weight copolymers is carried out in the presence of only small amounts of polymerization regulators or in the absence of these substances. Examples of polymerization regulators are 2-mercaptoethanol, mercaptopropanols, mercaptobutanols, thioglycolic acid, n-dodecyl mercaptan, tert-dodecyl mercaptan, thiophenol, mercaptopropionic acid, allyl alcohol and acetaldehyde. The polymerization regulators are used in an amount of from 0 to 10% by weight, preferably from 0 to 5% by weight, based on the monomers employed.
The polymers obtainable by the novel process are suitable for use as viscosity modifiers (emulsifiers and dispersion auxiliaries), as W/O and O/W emulsifiers and generally as process assistants, finishing assistants or as superabsorbents, furthermore as detergent additives, such as encrustation and dye transfer inhibitors, as retention aids in papermaking, as flocculants in water treatment or for use in the area of food technology, for example as filtration aids or complexing agents.
The polymers are also particularly suitable as thickeners and gelling agents in cosmetic formulations, especially for skin and hair cosmetic preparations, such as hair treatments, hair lotions, hair rinses, hair emulsions, tip fluids, leveling agents for permanent waves, hot-oil treatments, setting lotions or hair sprays, in particular in skin and hair conditioners.
Depending on the area of application, the hair cosmetic preparations can be applied as sprays, foams, gels, gel sprays or mousses.
The polymers are furthermore suitable as auxiliaries in pharmaceutical formulations, for example as tablet disintegrants.
The polymers prepared in accordance with the invention are white, free-flowing powders having a uniform morphology and virtually no tendency to stick.

Method for producing powder-shaped cross-linked polymerizates