JPH0641500B2 - Method for producing polymer product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for making a polymer product using a trimeric polyisocyanate and an unsaturated compound derived from an unsaturated monomer containing an isocyanate-reactive group.

In recent years, the use of glass fiber reinforced thermosetting resins for various purposes is gradually increasing. This is attributed to their overall performance, such as dimensional stability, strength, high temperature resistance and coatability. Other advantages are ease of handling and good workability. However, these polyester systems still have certain drawbacks, such as brittleness, and are subject to impact and fatigue problems. There is also a need to improve surface properties and shrinkage control.

To overcome these problems, various additives have been introduced into polyester sheet molding compounds (SMC) and bulk molding compounds (BMC). For example, 4 of 1977
U.S. Pat. No. 4,020,036 to Aubrey South, Jr. on March 26, shows that a liquid polymer such as polybutadiene is added to strengthen the polyester product. There is. However, since these materials are essentially immiscible with the polyester, these additives cannot be added to the polyester until the time when the resin and glass fiber are mixed. Saturated diacid (d
iacids) or long chain glycols have also been used to make polyester resins. The resulting product is softened, but its mechanical and thermal properties deteriorate.

Another study is the introduction of urethane-based polyester resins. U.S. Pat. No. 4,062,826 issued to Francis Gowland Hutchinson et al on Dec. 13, 1977 discloses a precursor of cross-linked polyurethane in a mixture of ethylenically unsaturated polyester and vinyl monomer. It has been shown to polymerize at room temperature to form a product with a polyurethane gel network penetrating into the polyester cross-linking structure. It has also been reported that higher impact properties are obtained, but the fine surface finishes required for many applications such as car bodywork have not been completed. Forger (G.) enhanced SMC (T
oughened SMC) ["Plastics World", page 63 (1978)
June year)]]. Moreover, this type of two-phase system is believed to lead to the formation of microvoids in the structure of the polymer product. Therefore, it is difficult to obtain a uniform color depth when adding pigments to the formulation.

Now, the present invention is a method for producing a polymer product which satisfies these requirements, namely, a polymer which comprises polymerizing a selected unsaturated compound, a free radical generating catalyst and a reinforcing material and / or a filler. It is a method for producing a product.

In the practice of the present invention, a molded plastic having the desired shrinkage control and pigmenting properties and suitable for many of the same applications as thermosetting polyester resin compositions such as equipment frames, electrical components and tools, etc. Manufactured.

The unsaturated compound in the present invention is a polyisocyanate reactant including a polyisocyanate mixture containing 30 to 70% of trimer polyisocyanate, preferably 45 to 60%, and an unsaturated monomer containing an isocyanate reactive group. It is prepared by reacting. This reaction uses methods well known in the art and has an equivalent ratio of active hydrogen to NCO of 1
The reaction is performed at 1/1 to 1.2 / 1, preferably 1/1 to 1.1 / 1.

By reacting this polyisocyanate reactant with an unsaturated monomer containing an isocyanate-reactive group, an unsaturated compound having a terminal reactive unsaturated group and having a controlled molecular weight is produced.

The reaction is preferably promoted by using a catalyst. Conventional urethane catalysts such as tertiary amines and metal compounds such as stannas octoate and dibutyltin dilaurate can be used. Any amount of catalyst can be used, but depending on, for example, the particular catalyst used, the amount will vary, which is about 0.01 of unsaturated compound.
Is in the range of up to 1% by weight. The reaction is also preferably carried out in the presence of a reactive copolymerizable solvent. Suitable copolymerizable solvents include styrene, substituted styrenes (eg, α-methylstyrene, chlorostyrene, etc.), vinyltoluene, divinylbenzene, esters of acrylic acid and methacrylic acid (eg, methyl) well known to those skilled in the art. There are vinyl compounds such as methacrylate, butyl acrylate etc.), allyl esters (eg diallyl phthalate, diallyl fumarate etc.) and the like. According to a particularly preferred embodiment of the invention, styrene is used. The amount of copolymerizable solvent used varies over a wide range. However, generally, the copolymerizable solvent is about 0 to 70 parts by weight, preferably about 3 parts by weight, per 100 parts by weight of the unsaturated compound and the copolymerizable solvent.
Used in an amount of 0 to 50 parts by weight. Both reaction temperature and time depend on many factors. For example, when the reaction is carried out in the presence of a copolymerizable solvent, a reaction temperature of about 40 ° C to 90 ° C and a reaction time of about 2 hours to 20 hours are preferable.

A polyisocyanate mixture containing a trimer polyisocyanate is prepared by mixing an isocyanurate group-forming catalyst with an organic polyisocyanate to be trimerized. To carry out the trimerization reaction, a combination of a quaternary ammonium carboxylate and a carboxylic acid halide or an anhydride is used as an isocyanurate group-forming catalyst. The catalyst contains 0.1 to 10 mmol of quaternary ammonium carboxylate per mol of organic polyisocyanate and 0.2 to 3 mmol of carboxylic acid halide or anhydride per mmol of quaternary ammonium carboxylate. The catalyst comprises in particular about 0.4 to 4 mmol of quaternary ammonium carboxylate per mole of organic polyisocyanate and about 0.4 to 1 mmol of carboxylic acid halide or anhydride per mmol of quaternary ammonium carboxylate. Is preferred.

Any organic polyisocyanate, including pure and unpurified compositions, can be used in forming the polyisocyanate mixture containing the trimer polyisocyanate of the present invention. These include alkyl polyisocyanates having up to about 10 carbon atoms and aryl, cycloalkyl, aralkyl and alkaryl polyisocyanates having up to about 30 carbon atoms. Representative examples are ethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, phenylene diisocyanate, methylene bis (cyclohexyl isocyanate), cyclohexylene diisocyanate, naphthalene diisocyanate, tolyl triisocyanate, methane tris (phenyl isocyanate) and all isomers and their isomers. Including a mixture. In a preferred embodiment of the invention, a mixture of isomers of 2,4- and 2,6-toluene diisocyanate is used. In particular, the weight ratio of 2,4-isomer to 2,6-isomer is about 60:40 to 90: 1.
0, more preferably about 65:35 to 80:20.

The quaternary ammonium carboxylates used in the preparation of polyisocyanate mixtures containing trimer polyisocyanates have the general formula: (However, R ₁ is hydrogen, C ₁ -C ₁₈ alkyl, C ₆ -C
Selected from the group consisting of ₂₄ aryl, C ₅ -C ₂₄ cycloalkyl, C ₇ -C ₂₄ aralkyl and C ₇ -C ₂₄ alkaryl, wherein R ₂ , R ₃ , R ₄ and R ₅ are each the same as R ₁ . , Or, independently, C ₁ -C ₁₈ alkyl, C
₆ -C _{24 aryl,} C 5 -C ₂₄ cycloalkyl, _{C 7} -
It is selected from the group consisting of C ₂₄ aralkyl and C ₇ -C ₂₄ alkaryl. ) Quaternary ammonium carboxylates can be readily prepared by methods well known in the art. For example, these carboxylic acid salts can be prepared by reacting the corresponding carboxylic acid with the corresponding quaternary ammonium hydroxide as in formula (A) below.

Suitable carboxylic acid reactants include the following compounds as well as mixtures thereof. Formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, stearic acid, octadecanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, benzoic acid, toluic acid,
Chlorobenzoic acid, phenylacetic acid and their analogues.

Suitable quaternary ammonium hydroxide reagents include the following compounds as well as mixtures thereof. Tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, tetraoctylammonium hydroxide, trimethylethylammonium hydroxide, tributylethylammonium hydroxide,
Triethylbutylammonium hydroxide, hexadecyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, phenyltrimethylammonium hydroxide and the like.

Quaternary ammonium carboxylic acid salts can also be prepared by reacting the alkali metal salt of the corresponding carboxylic acid with the corresponding quaternary ammonium halide as shown in formula (B) below.

(However, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are the same as above,
M represents an alkali metal such as Na or K, and X represents a halogen atom. ) Suitable reagents include alkali metal salts derived from the above carboxylic acids and quaternary ammonium halides such as the following compounds and mixtures thereof: tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium. Bromide, tetraoctylammonium chloride, trimethylethylammonium chloride, tributylethylammonium chloride, triethylbutylammonium chloride, hexadecyltrimethylammonium chloride, benzyltriethylammonium chloride, phenyltrimethylammonium hydroxide and the like.

Any suitable conventional reaction conditions can be used in the synthesis of the quaternary ammonium carboxylate. formula
The reaction of (A) and formula (B) is suitably carried out using either of the reactants in a molar excess, but it is preferable to carry out the reaction using an equimolar amount of the reactant.

Quaternary ammonium carboxylates used to prepare polyisocyanate mixtures containing trimer polyisocyanates include, for example, the following compounds: tetramethylammonium acetate, tetraethylammonium acetate, tetramethylammonium propionate, tetra Methylammonium octanoate, tetramethylammonium-2-ethylhexanoate, tetrabutylammonium-2-ethylhexanoate, benzyltriethylammonium acetate, phenyltrimethylammonium-2-ethylhexanoate, tetrabutylammonium benzoate and the like.

Preferred quaternary ammonium carboxylates are those of the general formula above, wherein R ₁ is selected from the group consisting of hydrogen and C ₁ -C ₁₈ alkyl, and R ₂ , R ₃ , R ₄ and R ₅ are Independently C ₁
Selected from the group consisting of -C ₁₈ alkyl and C ₇ -C ₂₄ aralkyl. In a particularly preferred embodiment of the invention tetrabutylammonium-2-ethylhexanoate and benzyltriethylammonium acetate are used.

Any suitable halide or anhydride derived from an aliphatic or aromatic carboxylic acid is used to form the polyisocyanate mixture containing the trimer polyisocyanate. Typically, the halide or anhydride is obtained from a carboxylic acid reactant containing 2 to 18 carbon atoms, usually 4 to 12 carbon atoms. These carboxylic acid reactants include the following compounds and mixtures thereof: acetic acid, propionic acid, butyric acid, valeric acid, caproic acid,
Aliphatic carboxylic acids such as lauric acid, stearic acid and their analogs, aromatic carboxylic acids such as benzoic acid, toluic acid, chlorobenzoic acid and their analogs. Carboxylic acid halides are a preferred class of compounds. A particularly preferred carboxylic acid halide is benzoyl chloride.

Various types of reaction conditions can be used to carry out the trimerization reaction. No solvent is required, but any suitable inert solvent can be used. Representative examples are the following compounds: cellulose acetate, ethyl acetate,
Butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl ether, dioxane, benzene, toluene, xylene and dimethylformamide.

Furthermore, the reaction temperature and reaction time both depend on many factors, including the organic polyisocyanate to be trimerized, the exact catalyst used, and the like. Under the most common conditions, the reaction temperature is about 50-120 ° C and the reaction time is about 1-16 hours, but a temperature range of about 80-100 ° C is preferred. Three
Since the oligomerization is a high temperature exothermic reaction, cooling may have to be used to keep the temperature of the reaction mixture in the above range.

The trimerization step can be carried out by mixing the organic polyisocyanate to be trimerized with the quaternary ammonium carboxylate and the reagents used to form the carboxylic acid halide or anhydride. .
According to this embodiment, the desired quaternary ammonium carboxylate salt is generated in situ for use in the trimerization reaction.

A very effective way to control the trimerization of organic polyisocyanates is to use selected isocyanurate group-forming catalysts in the present invention. A mixture containing unreacted polyisocyanate, trimer and high molecular weight trimers is obtained, which is substantially completely soluble in the copolymerizable solvent when used to practice the invention.

The proportion of trimer polyisocyanate in the mixture can be varied by many factors, such as reaction temperature, time and the like. However, it is generally preferred to carry out the reaction so that 30-70% of the trimer polyisocyanate is included in the polyisocyanate mixture. The mixture is 45
It is particularly preferred to contain ˜60% of trimer polyisocyanate.

The resulting mixture is then used as such or diluted with additional organic polyisocyanate to provide the polyisocyanate reactant used in accordance with the invention. The polyisocyanate mixture containing the trimer polyisocyanate is preferably used as or as part of a polyisocyanate reactant.
If desired, a polyisocyanate mixture with a high content of trimer polyisocyanate is prepared and then diluted with additional organic polyisocyanate to the desired trimer polyisocyanate content.

Unsaturated monomer containing a suitable isocyanate-reactive group, a hydroxyl group-containing or amino group-containing acrylate,
Included are substituted acrylates such as methacrylate, acrylamides, substituted acrylamides such as methacrylamide, and mixtures thereof. Isocyanate-reactive group-containing unsaturated monomers include, for example, hydroxyalkyl acrylates such as hydroxyethyl acrylate and hydroxypropyl acrylate, hydroxyalkyl methacrylates such as hydroxyethyl methacrylate and hydroxypropyl methacrylate, hydroxyethyl acrylamide and hydroxypropyl acrylamide. Hydroxyalkyl acrylamide, such as
Included are hydroxyalkyl methacrylamides such as hydroxyethyl methacrylamide and hydroxypropyl methacrylamide, glycerol monoacrylate, glycerol dimethacrylate, trimethylolpropane dimethacrylate, pentaerythritol triacrylate and the like and mixtures thereof.
Hydroxyalkyl acrylates, hydroxyalkylmethacrylates and mixtures thereof are preferred, hydroxyethylmethacrylate being most preferred.

Other reagents, such as chain extenders and mixtures thereof, may also be included in the reaction mixture in forming the unsaturated compound. These chain extenders have an average equivalent weight of about 31-4,000, preferably about 31-500, and an average functionality of about 2. Suitable chain extenders include the following compounds and mixtures thereof: (a) ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, 2-ethyl-1,3-hexanediol,
Low molecular weight diols such as diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, bisphenol A and their analogs and (b) polyoxyls such as oxypropylene diol, oxypropylene-oxyethylene diol and their analogs. Ether diol. Propylene glycol and tripropylene glycol are particularly preferred. When used, the proportion of chain extender is generally about 0.05 to 0.6, preferably about 0.1 to 0.4 equivalents per equivalent of active hydrogen.

Unsaturated compounds polymerize and cure in the presence of free radical generating catalysts. The actual cure conditions can be varied over a wide range and will generally depend on the nature and amount of the particular catalyst used. Suitable free radical generating catalysts include peroxide or azo type compounds well known in the art. Representative peroxide catalysts are benzoyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, lauryl peroxide, cyclohexanone peroxide, t-butylbenzene perbenzoate, t-butyl hydroperoxide, t-butylbenzene hydroperoxide, cumene hydro. Peroxide, t
-Organic peroxides and hydroperoxides such as butyl peroctoate and their analogues. Representative azo compounds are azobis-isobutyronitrile, 2-t-butylazo-2-cyano-4-methylpentane, and 4-t-butylazo-4-cyano-.
It is valeric acid. The preferred catalyst is a peroxide catalyst. Particularly preferred peroxide catalysts are t-butyl peroctoate, t-butyl perbenzoate and mixtures thereof. Although any suitable amount of catalyst can be used,
Generally, the catalyst is used in an amount of about 0.5 to 10 parts by weight per 100 parts by weight of unsaturated compound.

The compositions of the present invention also include at least one filler or reinforcing material. In a particularly preferred embodiment of the present invention, both filler and reinforcement are included. Any material known in the art to be suitable as a filler can be used. In general, various materials such as CaCO ₃ ,
Finely divided solids including clay, alumina, talc, glass microspheres and the like can be used. Also, any suitable reinforcement such as chopped glass fibers, carbon fibers, asbestos fibers, boron nitride whiskers and the like can be used. The amount of filler included in a typical formulation can vary considerably, but is generally about 100 to 1.00 per 100 parts by weight of unsaturated compound.
It is in the range of 0 parts by weight, preferably about 160 to 500 parts by weight. If a reinforcing material is added to the formulation, its amount can also be varied within wide limits. However, a typical formulation is generally about 40-80 per 100 parts by weight of unsaturated compound.
0 parts by weight, preferably about 100 to 400 parts by weight.

The composition also optionally contains other standard reagents such as internal mold release agents such as calcium stearate, zinc, magnesium or sodium. Low shrinkage or impact resistant additives can also be included as desired. Pigments, dyes, stabilizers, thixotropes and other additives well known to those skilled in the thermosetting polyester art can also be added.

The following examples serve to further illustrate the invention,
Parts are parts by weight unless otherwise stated.

Preparation of unsaturated compounds Example 1 To 940 g (5.4 mol) of diisocyanate was added 1 ml (8.6 mmol) of benzoyl chloride, 4.42 g (19.4 mmol) of benzyltriethylammonium chloride and 1.92 g (19.4 mmol) of finely ground potassium acetate. It was Then
Heating the resulting mixture to 80 ° C. to initiate trimerization,
The reaction mixture was stirred at about 85 ° C. overnight and then 2,6-di-
680 mg t-butyl-4-methylphenol (BHT) and 1360 g styrene were added. After cooling, 1100 g (8.45 mol) of unsaturated monomer was added and the reaction mixture was stirred overnight without heating. Then, 7.0 g of catalyst and 510 mg of phenothiazine were added, and the reaction mixture was stirred for 1 hour without heating and then at 90 ° C. for 2 hours to complete the reaction. The product had a viscosity of 70 cps.

[Note] This is the toluene diisocyanate isomer (2.4 /
2.6-80: 20 mixture of isomers).

Hydroxyethyl Methacrylate This is stance octoate and is commercially available from M & T Chemicals Inc. under the trade name "T-9".

Example 2 470 g (2.7 mol) of diisocyanate was mixed with benzoyl chloride 1
ml (8.6 mmol) and tetrabutylammonium-2
3.0 g (7.8 mmol) of ethylhexanoate were added.
The resulting mixture is then heated to about 60 ° C. to initiate trimerization and the reaction mixture is stirred at 50-90 ° C. for 2 hours, then
Styrene 988.3g, unsaturated monomer 368.5g (2.83mol),
149.8 g (0.78 mol) tripropylene glycol and BHT
395 mg was added. The reaction mixture was stirred for 1 hour, then 3.95 g of catalyst and 296 mg of phenothiazine were added and stirring was continued overnight. The reaction mixture was then heated to 90 ° C. for 3-1 / 2 hours to complete the reaction. The product had a viscosity of 100 cps.

[Note] is the same as in Example 1.

Example 3 To 261 g (1.5 mol) of diisocyanate was added benzoyl chloride.
0.7 ml (6.0 mmol) and 2.1 g (6.0 mmol) tetrabutylammonium-2-ethylhexanoate were added. The resulting mixture was heated to about 90 ° C. to initiate trimerization, and the reaction mixture was stirred at 70 ° C. for 2 hours, after which 459 g of styrene, 263.5 g (2.03 mol) of unsaturated monomer, and 34.2 propylene glycol. g (0.45 mol) and BHT 214 mg were added. , Stirring was continued overnight, after which 2.14 g of catalyst and 153 mg of phenothiazine were added. The reaction mixture was then stirred without heating for 1 hour and then heated to 90 ° C. for 1 hour to complete the reaction. The product had a viscosity of 15,000 cps.

[Note] is the same as in Example 1.

Example 4 To 261 g (1.5 mol) of diisocyanate was added benzoyl chloride.
0.7 ml (6.0 mmol) and 2.1 g of tetrabutylammonium-2-ethylhexanoate (6.0 mmol) were added. The resulting mixture was heated to about 90 ° C. to initiate trimerization and the reaction mixture was stirred at 90 ° C. for 3 hours before adding 538 g of styrene, 225.5 g (1.73 mol) of unsaturated monomer, glycerol diester. 169g of methacrylate (0.74mol) and 239m of BHT
g was added. Stirring is continued overnight, after which the catalyst is added to 2.3.
9 g and phenothiazine 179 mg were added. The reaction mixture was then stirred without heating for 1 hour, then 1-1 / 2 hours 9
The reaction was completed by heating to 0 ° C. The product had a viscosity of 70 cps.

[Note] is the same as in Example 1.

Preparation of Fiber Reinforced Moldings Example 5-8 Fiber reinforced products containing unsaturated compounds prepared according to Examples 1 to 4 were prepared. The molding formulations used are summarized in Table 1 below. The following method was used to prepare the cured composition.

(a) Unsaturated compound, styrene, low shrink additive (if desired), catalyst and pigment were added to a high shear mixer.

(b) The filler was added slowly and mixed until a homogeneous paste was obtained.

(c) Next, add 2 pieces of chopped glass fiber to the paste.
-Added in a roll mill, Baker Perkins mixer or rosterable planetary mixer and processed the mixture for the shortest time to remove the moisture from the glass with almost no damage to the glass.

(d) The uncured mixture was then placed in a mold between the hot plates of a compression molding machine and cured under pressure (700 psi) at 300-325 ° F for 2 minutes.

(e) Instead of (d), the mixture is added by a hopper to the screw system of an injection molding machine to make an injection molded part, or the mixture is loaded into an SMC machine and then subjected to compression molding or injection molding.

Comparative Examples 1 to 3 For comparison, fiber reinforced moldings containing various commercially available resins were prepared according to the methods of Examples 5 to 8. The molding process used is shown in Table 1 below. The pigmentation (coloring) and shrinkage control properties of the moldings prepared by this method are also shown in Table 1 below.

Comparing the results, the moldings prepared in Comparative Example 1 show excellent pigmenting properties, but poor shrinkage control (sample warped). On the other hand, the molded article prepared in Comparative Example 2 showed excellent shrinkage control but poor pigmentation properties.
The product of Comparative Example 3 exhibited poor shrinkage control (sample warped) and poor pigmentation properties. These results show that moldings made from conventional resins do not have good shrinkage control and pigmenting properties. However, the composites made from the unsaturated compounds of the present invention simultaneously exhibited excellent shrinkage control and pigmentation properties.

It should also be noted that the black pigment was used to carry out these examples and comparative examples. Black is generally considered to be the most difficult color to use to find a uniform color depth. Therefore, it is natural that the composition of the present invention is much more excellent as a result of using other colors.

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Claims (3)

[Claims] 1. A method for producing a polymer product, which comprises uniformly mixing an unsaturated compound, a free-radical generating catalyst, and a reinforcing material and / or a filler, and then polymerizing the unsaturated compound. , (A) a polyisocyanate reagent containing a polyisocyanate mixture containing 30 to 70% of a trimer polyisocyanate, (b) a hydroxyl group-containing or amino group-containing (i) acrylate, (ii) substituted An isocyanate-reactive group-containing unsaturated monomer selected from the group consisting of acrylates, (iii) acrylamides, (iv) substituted acrylamides, and (v) mixtures thereof; The polyisocyanate mixture containing the trimer polyisocyanate is prepared by reacting at an equivalent ratio of active hydrogen to NCO of 2/1. Those prepared by trimerizing the polyisocyanate in the presence of a rate group forming catalyst, a quaternary ammonium carboxylate salt of polyisocyanate per mole of the following formula as the catalyst 0.
1. A process for producing a polymer product, which comprises using 1 to 10 mmol and 0.2 to 3 mmol of carboxylic acid halide or anhydride per 1 mmol of the quaternary ammonium carboxylate. (However, R ₁ is hydrogen, C ₁ -C ₁₈ alkyl, C ₆ -C
Selected from the group consisting of ₂₄ aryl, C ₅ -C ₂₄ cycloalkyl, C ₇ -C ₂₄ aralkyl and C ₇ -C ₂₄ alkaryl, wherein R ₂ , R ₃ , R ₄ and R ₅ are each the same as R ₁ . , Or, independently, C ₁ -C ₁₈ alkyl, C
₆ -C _{24 aryl,} C 5 -C ₂₄ cycloalkyl, _{C 7} -
It is selected from the group consisting of C ₂₄ aralkyl and C ₇ -C ₂₄ alkaryl. ) 2. The polyisocyanate reactant is 45-60.
The process according to claim 1, which comprises a polyisocyanate mixture containing 10% of trimer polyisocyanate. 3. The method according to claim 1, wherein the unsaturated monomer is selected from the group consisting of hydroxyalkyl acrylate, hydroxyalkyl methacrylate and mixtures thereof.