KR890002710B1 - Copolymerization of unsaturated urethane monomers - Google Patents

Abstract

A moulded plastics product is produced by a method which comprises the steps of introducing a polymerisable composition into a mould, in which polymerisable composition comprises an unsaturated urethane cpd. (A) and a vinyl monomer (B) copolymerisable therewith. The unsaturated urethane cpd. (A) is a polyurethane polyacrylate or polymethacrylate resin derived from a hydroxyl gps. thereof with the isocyanate gps. having an isocyanate functionality greater than 2.0 or a urethane polyisocyanate derived from a polyisocyanate by reaction with the hydroxyl gps. of diol triol. The vinyl monomer is methylmethacrylate.

Description

Copolymerization Method of Unsaturated Urethane Monomer

The present invention relates to the copolymerization of unsaturated urethane monomers, in particular to the 'in mold' copolymerization process of certain polyurethane polyacrylates and polyacrylates and compositions used therein.

In the molding of plastic products and parts, a promising, attractive and economical way is to inject the liquid component to be polymerized into the mold and to quickly carry out in-mold polymerization. In such a molding process, the time required for the polymerization is 10 minutes or less, preferably 5 minutes or less (possibly within 2 minutes). It is also preferred that such rapid polymerization is carried out at ambient temperatures or at temperatures which are not much elevated above ambient, such as initial mold temperatures of 60 ° C. or lower.

The properties required for the polymerizable composition to use the casting method are distinguished from the properties required for other compositions, such as those used in protective coatings of pitch rings. Until now, the use of polymerizable or copolymerized vinyl monomers has been limited in the molding process due to the lack of polymerizable compositions capable of polymerizing at the required rate at a suitable temperature and producing a polymer product that is sufficiently rigid to be removed from the mold.

U.S. Patent No. 3,856,830 and its subdivision 3,954,714 disclose reaction products which react with (a) an organic polyisocyanate having at least triisocyanate groups and (b) hydroxy terminated and reacted with the stoichiometric amounts of esters unsaturated with ethylene and with the mentioned isocyanate groups. Certain ethylenically unsaturated urethane monomers are described. The urethane monomers described are derivable from various esters terminated with various hydroxys, and the monomers mentioned are useful for the preparation of various pure polymers and copolymers as well as mixed resins. Examples are given for the preparation of copolymers having styrene and styrene or butyl methacrylate and styrene or divinylbenzene, most of which are reacted first with the main reactants at room temperature for about 16-24 hours, followed by 1 The reaction product is said to cure in the temperature range of 80 ° C-175 ° C for -6 hours.

Currently, we have found that by utilizing certain polyurethane polyacrylates or polymethacrylates in combination with methylmethacrylate, a comonomer, rapid “in-mold” polymerization can be advantageously performed.

According to the present invention a method of casting a plastic product by casting a vinyl monomer copolymerizable with an unsaturated urethane compound "in a mold" is proposed. The characteristic of this is that (a) an unsaturated urethane compound is polyurethane polyacrylate or polymethacrylate resin derived by making the hydroxyl group of an hydroxyalkyl acrylate or methacrylate react with an isocyanate group. The isocyanate group is i) a urethane polyisocyanate having no urethane group and derived by reacting a polyisocyanate having 2.0 or more isocyanate functional groups or ii) a polyisocyanate with a hydroxy group of an aliphatic alcohol having up to three hydroxy groups, and having 2.0 or more isocyanate functional groups. to be. (b) the vinyl monomer is methyl methacrylate.

The hydroxyalkyl acrylate or methacrylate preferably contains 2-4 carbon atoms in the hydroxyalkyl group. Particular preference is given to 2-hydroxy ethyl and 2-hydroxy propyl acrylate and methacrylate.

When a polyurethane polyacrylate or polymethacrylate is derived from a urethane polyisocyanate, the urethane polyisocyanate is a polyurethane polyisocyanate derived by the reaction of an aliphatic dihydric or trihydric alcohol with a polyisocyanate having an isocyanate functional group of 2.0 or more More preferred.

Polyisocyanates which are particularly good for the direct reaction with hydroxyalkyl acrylates or methacrylates and for the preparation of intermediate polyurethane polyisocyanates are polyethylene polyphenyl polyisocyanates.

When the polyurethane polyisocyanate is derived from a diisocyanate (e.g. diphenyl-methane-4, 4'-diisocyanate or other aromatic diisocyanate), a trihydric alcohol that produces a polyurethane polyisocyanate having a desired isocyanate functional group of at least 2.0 Reaction is required.

Suitable dihydric and trihydric alcohols are those commonly used in the art of reacting isocyanates with polyhydric alcohols to produce urethanes.

Suitable dihydric alcohols are glycols of the general formula OH-Q-OH. Wherein Q is an alkylene or polyalkylene ether group, i.e., dihydricphenol and bis-phenol, such as 2, 2-bis (4-hydroxyphenyl) propane (bisphenol A) and bis (4-hydroxyphenyl) sulfone (Bisphenol S).

Suitable trihydric alcohols include glycerol, trimethol propane (1, 1, 1-tris (hydroxymethyl) -propane) and their ethoxy or propoxy derivatives.

The reaction product may comprise a ratio of one or more polyurethanes of high molecular weight derived from the reaction of the above products with the polyhydric alcohols and polyisocyanates of the macromolecules.

The average number of isocyanate functional groups (i.e., isocyanate groups per molecule) of the polyisocyanate (or polyurethane polyisocyanate) used is preferably in the range of at least 2, 2, for example 2.5-3.0. The polyisocyanate may be one polyisocyanate Or a mixture of polyisocyanates having the above-described average functional groups.

In the polyurethane polyisocyanate preparation, the ratio of polyisocyanate and polyhydric alcohol is selected such that all of the hydroxy groups of the polyhydric alcohol are modified with urethane groups. The result is larger than the isocyanate functional groups of the polyurethane polyisocyanate. For example, if the initial polyisocyanate has a functional group n of 2.5, the isocyanate functional group of the polyurethane polyisocyanate derived from the dihydric alcohol is 2n-2 = 3.0.

Regardless of which polyhydric alcohol is used, the relative proportions of polyhydric alcohols and polyisocyanates and / or isocyanate functional groups of the polyisocyanates are chosen to produce the required isocyanate functional groups in the polyurethane polyisocyanate.

The polyurethane polyacrylate or polymethacrylate of the present invention reacts a hydroxyalkyl acrylate or methacrylate with a polyisocyanate (or urethane polyisocyanate) having a functional group of 2.0 or more to produce polyurethane in the present technology. It manufactures using the method used normally.

If desired, a mixture of two or more hydroxyalkyl acrylates and / or methacrylates may be used, with the relative proportion of reactants used providing at least 1 mole of hydroxyalkyl acrylates or methacrylates per isocyanate group. It is preferable to do so. Excess (unreacted) hydroxyalkyl acrylates or methacrylates in the reaction product are usually acceptable as the excess is simply bound in the resulting copolymer, mostly in the course of the copolymerization. The excess range of hydroxyalkyl acrylates or methacrylates is determined by the practical considerations of economic considerations and by the desire to bond certain hydroxyalkyl acrylates or methacrylates in the final copolymer.

Catalysts used in the reaction between hydroxyalkyl acrylates or methacrylates and polyisocyanates (or urethanepolyisocyanates) are known in the art of polyurethane production, for example tertiary amines and metal salts, in particular di-n-butyltin Dirorate.

The reaction between hydroxyalkyl acrylate or methacrylate and polyisocyanate (or urethane polyisocyanate) is preferably carried out in the presence of an inert liquid diluent. Diluents can be used extensively, but the reaction is carried out in the presence of methylmethacrylate as a diluent to avoid separation of polyurethane polyacrylates or polymethacrylates.

Similarly the copolymerization of polyurethane polyacrylate or polymethacrylate with methyl methacrylate can be carried out using techniques well known in gas copolymerization techniques. The polymerization initiator and its concentration can be used in various ways depending on the desired temperature and degree of polymerization. For example, the catalyst can be a peroxide catalyst, which can be used in conjunction with tertiary amine promoters. For example, N-N-diethylaniline or dibenzoyl peroxide associated with N, N-dimethyl-para-toluidine is in many cases suitable compounds.

The relative emptying of the polyurethane polyacrylates or polymethacrylates and the methyl methacrylate monomers to be copolymerized with them will depend on the properties required for the copolymerization product and the copolymerization conditions used. Typically, the ratio of polyurethane polyacrylate and / or polymethacrylate is 10-90 (e.g. 25-75, in particular 100-polyurethane polyacrylate and / or polymethacrylate + methyl methacrylate by weight). 25-50) is preferred.

The mechanical properties (eg flexural strength and flexural modulus) of the mentioned copolymerization products can be tolerated for the intended use without the introduction of additional components. However, sometimes it is desirable to act the reaction mixture and the filler before copolymerization to enhance the mechanical properties. For example, inorganic fillers may be combined with particles, plates or fibrous forms, and suitable fillers include silica, calcium carbonate, talc, alumina trihydrate, mica, various clays and vermiculite. For example, glass fibers having a surface ratio of 10/1 to 500/1 (particularly 20 / 1-300 / 1), or continuous, can be used as fillers.

When an inorganic filler is used, a suitable "couping agent" may be advantageously combined to connect the filler with the polymer matrix. For example, when the filler is silica, suitable silane coupling agents, for example r-methacryl-oxypropyl-trimethoxysilane, may be blended.

Organic polymers, in particular thermovisible polymers, can be combined in the reaction mixture before copolymerization. One or more organic polymers may be dissolved in the reaction mixture, or added in particulate form, irrespective of the action of the inorganic fillers already described. Polymers that can be formulated include polymers and copolymers of alkyl acrylates and / or methacrylates (especially acrylates and / or methacrylates such as methyl methacrylates containing 1-8 carbon atoms in an alkyl group). Includes; Ie polymers and copolymers of styrene and α-methylstyrene (eg copolymers of styrene with butadiene); Polymers and copolymers of acrylonitrile (eg copolymers of styrene with acrylonitrile); Combinations of polymers and copolymers of vinyl chloride (eg, copolymers of vinyl chloride with vinyl acetate) and polymers and copolymers of vinyl acetate are often useful to reduce main form shrinkage.

Typically, the proportion of organic polymer to be blended is, for example, 1-25 (particularly 3-10) per 100 weight of methyl methacrylate and polyurethane acrylate or methacrylate, with the upper limit being the desired viscosity and final product of the mixture. Depends on the desired mechanical properties.

Other adducts, such as plasticizers and colorants, are known in the art and may be combined.

In particular, a preferred use of the polyurethane polymethylacrylate resin solution in methylmethacrylate described herein is the production of fiber reinforced compositions, especially glass fiber reinforced compositions by automated processes.

In such processes—for example, closed mold processes using coordinated male and female molds—glass fiber reinforcement (cut-strand-strand mat continuous filament mat woven continuous filament mats or different variations of the mat ) Is placed in the half of the mold to close the mold, and flow the resin to vacuum the cavity of the closed mold and to absorb the resin, or to pump the resin, or to use a vacuum and a pump together. Wet fiber reinforcement. In a variant, the liquid resin is placed in the half of the female mold and the resin is flowed into the glass fiber by closing the mold.

For improved efficiency and speed in such processes, excess resin is introduced to quickly wet the fiber reinforcement, minimize mammals such as bubbles or voids, and "wash" the glass fibers (movement of the glass fibers by resin inflow). It is advantageous to minimize the industrial terminology described above, and also to introduce it through fiber reinforcement under minimum pressure. This advantage is more easily obtained when the resin is of low viscosity. Next, the mold cavity will once be filled with resin, and the resin will polymerize quickly, resulting in a product that has solidified so tightly that it can be cast out. The advantage of the polyurethane polyacrylates and polymethacrylates described in the present invention is that they are solutions dissolved in methyl methacrylate with very low viscosity and do not utilize rapid polymerization properties.

Typically, the viscosity of the polyurethane polyacrylate or a mixture of polymethacrylate and methyl methacrylate is not more than 200 centipoise. That is, less than 100 centipoise viscosities, such as 5-50 centipoise, are particularly preferred (viscosity throughout this specification is measured at 20 ° C. with a Brookfield viscometer at 600 rpm; 1 centipoise = 1 mpa). .S).

The addition of a relatively high inorganic filler provides additional benefits in that it results in a low viscosity resin and maintains the advantageous process described previously to perform with a polyurethanepolymethacrylate resin and a relatively low viscosity solution.

Polyurethane polymethacrylate resin solutions in methyl methacrylate may also be used in the pultrusion process.

The invention is presented by the following examples. Unless otherwise specified, all percentages and parts are by weight.

Example 1

Polyisocyanate 'suprasec' DND used in this example, ie a mixture of 4, 4-diisocyanato-diphenylmethane and associated polymethylene polyphenyl polyisocyanate, having an average isocyanate functional group of 2.6 ('Suprasek' is a trademark).

'Suprasek' DND (215 g) is dissolved in methyl methacrylate (421 g including 60 PPm hydroquinone as polymerization inhibitor) and 2.2 g of di-n-butyltin dirorate is added. The solution is stirred at ambient temperature and 229 g of 2-hydroxyethyl methacrylate (containing 300 PPm of p-methoxyphenol as polymerization inhibitor) are added quickly (for 1 minute).

Three minutes after the end of the 2-hydroxyethyl methacrylate addition, the temperature of the mixture increased to 75 ° C due to the heat of reaction. With very little isocyanate content remaining (as measured by IR absorption), the reaction was practically completed at this stage. After heating the mixture at 90 ° C. for at least 6 hours, no isocyanate was detected.

The product became a brown solution in which 2-hydroxyethyl methacrylate and polyurethane polymethacrylate derived from polyisocyanate were dissolved in methyl methacrylate.

A slight portion of this solution was copolymerized to produce a copolymer comprising 40% polyupetane polymethacrylate and 60% methyl methacrylate.

50 g of polyurethane polymethacrylate solution and surroundings in which 12.5 g of methyl methacrylate (0.94 g of benzoyl peroxide) was dissolved in methyl methacrylate (0.19 g of N, N-dimethyl-P-toluidine was added thereto) Mix at temperature and inject the mixture between panes at 36 ° C.

The mixture was gelled for 60 seconds and reached the peak of exotherm after 105 seconds. The copolymer removed from the mold had a flexural strength of 10 mN / m 2 (the test measured the ratio of length and depth to 10: 1 and the speed of the movable crosshead at 2 mm / min).

Example 2

(a) Manufacturing method of polyurethane polyisocyanate.

The polyisocyanate used is a 'suprasec' DND with an average isocyanate functional group of 2.6 ('Suprasec' is a trademark).

A flask for 11 was filled with 100 g of molten polyethylene glycol (molecular weight 1000), 140 g of methyl methacrylate and 1 g of di-n-butyltin dirorate. The mixture was stirred at ambient temperature and 66 g of 'Suprasek' DND dissolved in 60 g of methyl methacrylate was added slowly over 10 minutes; During this addition, the temperature of the mixture increased to 45-50 ° C.

After the addition was complete, the mixture was stirred for at least 60 minutes when the temperature was reduced to 20-25 ° C.

(b) Polyurethane polymethacrylate manufacturing method by reaction of 2-hydroxyethyl methacrylate and polyisocyanate polyurethane.

43.8 g of 2-hydroxyethyl methacrylate was added to the polyurethane polyisocyanate prepared as described in (a) of this example. The temperature of the mixture increased to 45-50 ° C., maintained for more than 180 minutes, and eventually no free isocyanate was detected. The product was a solution containing equally the weight ratio of polyurethane polymethacrylate and methyl methacrylate.

(c) copolymerization of polyurethane polymethacrylate with methyl methacrylate.

Excess methyl methacrylate was added to the solution to reduce the concentration of polyurethane polyacrylate to 40% by weight in the polyurethane polymethacrylate solution prepared as described in (b). Dibenzoyl peroxide (weight ratio 1.5%) was added as a catalyst, and N, N-dimethyl-P-toluidine (weight ratio 0.3%) was added as an accelerator.

The mixture was cast into a glass cell (3 mm thick) at 26 ° C as the base temperature. After 5 minutes, the exothermic peak was reached, after which the resulting copolymer was a rigid plate that could be quickly removed from the cell.

Example 3

The general procedure of Example 2 was repeated with the following modifications. (a) The dihydric alcohol used was hexylene diol (2-methyl-pentane-2,4-diol), and 19.7 g of this dihydric alcohol was dissolved in 212 g of methyl methacrylate as a solvent, and the 'Suprasek' DND Reacted with (118.7); Di-n-butyltin diroate (1 g) is used as catalyst. (b) Polyurethane polymethacrylate, prepared by reacting the reaction product of dihydric alcohol and polyisocyanate with 88.1 g of 2-hydroxypropyl methacrylate, is dissolved in methyl methacrylate. The weight of acrylate was to comprise 50%. (c) Methyl methacrylate was added to the polyurethane polymethacrylate solution such that the weight ratio of polyurethane polymethacrylate in the solution was reduced to 25%. Copolymerization is carried out as described in Example 2 (c). The peak of smoke reached after 6.5 minutes, and the resulting copolymer was a rigid plate that could readily be removed from the cell quickly.

Example 4

In the following variant, the general procedure of Example 2 is followed. (a) Dissolving 38 g of bisphenol A of 230 g of methyl methacrylate as a solvent using bisphenol A as a dihydric alcohol and reacting with 'Suprasek' DND (118.7 g), but di-n-butyl as catalyst Use tindirorate. (b) A reaction product of bisphenol A and polyisocyanate was reacted with 81.8 g of 2-hydroxyethyl methacrylate to prepare a solution in which the weight ratio of polyurethane polymethacrylate was 50%. (c) Methyl methacrylate was added to the solution to produce a solution containing 50% by weight of polyurethane polymethacrylate.

Copolymerization is carried out as described in Example 2 (c). The exothermic peak reached after 6.75 minutes and the resulting copolymer was a rigid plate that could be removed from the cell quickly after the exothermic peak.

Example 5

As a polymerization inhibitor, 'Suprasek' DND (200 g) was dissolved in methyl methacrylate (250.8 g) containing 60 ppm hydroquinone, and 2.0 g of di-n-butyltin dirorate was added thereto. The solution is stirred at ambient temperature and 200 g of 2-hydroxyethyl methacrylate containing 300 ppm paramethoxyphenol as a total inhibitor is added quickly (for 1 minute). Due to the heat of reaction three minutes after the end of the 2-hydroxyethyl methacrylate addition, the temperature of the mixture increased to 80 ° C. The reaction actually terminated at this stage because there is very little residual isocyanate (as measured by IR absorption). For at least 5.5 hours, the mixture was heated at 90 ° C. so that no isocyanate could be detected.

The product was a brown solution containing 60% weight ratio of 2-hydroxyethyl methacrylate and polyurethane polymethacrylate derived from 'Supresec' DND and dissolved in methyl methacrylate.

Example 6

For comparison, 2-hydroxyethyl-methacrylate and polyurethane polymethacrylate derived from 'Suprasek' DND were prepared as styrene solutions.

The procedure is the same as described in Example 5, except that styrene (250.8 g with 10-20 ppm t-butyl catechol) was used instead of methyl methacrylate. The product was a brown solution dissolved in styrene (viscosity 80 centipoise) in which polyurethane polymethacrylate comprised 60% by weight.

Example 7

A freshly prepared solution sample of the polyurethane polymethacrylate resin prepared in Example 5 was diluted with methyl methacrylate (containing 60 ppm hydroquitone) so that the weight ratio of the resin was 50%, 40%, and 30%. A phosphorus solution was made. Viscosities were 20, 10 and 5 centepoise, respectively.

Similarly, a sample of the freshly prepared solution of the polyurethane polymethacrylate resin prepared in Example 6 was diluted with styrene (containing 10-20 ppm of tert-butyl catechol), so that the weight ratio of the resin was 50%, 40%. And 30% solution. Viscosities were 25, 10 and 5 centipoise, respectively.

The thermal conductivity of the polymerization of these solutions was depicted by measuring the time of the gel state and the time to the peak past the gel, according to the SPI general process for unsaturated polyester resins.

15 g of the resin solution to be tested was bisected and made equal. In one portion 0.15 g of dibenzoyl peroxide was added and in the other portion 0.05 g of N, N'-dimethyl-para-toluidine. In a glass bottle having an internal diameter of 25 mm, two were mixed to start polymerization of the resin and the monomer solution.

The onset of gel state (gel-time) was determined by immersing and squeezing a wooden rod with a diameter of 1 mm and observing the change in flow state. The change in flow rate for gelation is very unique and sudden, so the time at which the change occurs is measured with an accuracy of about ± 15%.

The maximum time is the time it takes for the polymerization exotherm to reach the maximum temperature after joining the bisected 15 g. The time from gel to peak is the difference between minimum time and gel-time. The exotherm is measured by inserting a chromel-alumel thermometer in the center of the resin and monomer samples.

Polymerization exotherm was measured with a resin solution immersed in a water bath with temperature control prior to initiation. Comparative data are obtained in a water bath at 23 ° C and 60 ° C.

Gel-hours, time to peak in the gel, and peak temperature records are shown in Table 1.

The material obtained when methyl methacrylate is used rather than styrene as a comonomer to copolymerize with polyufetane polymethacrylate resin suggests that the gel-times are similar and the time from gel to peak is significantly shorter.

Furthermore, the polyurethane polymethacrylate resin solution dissolved in methyl methacrylate was stable for a much longer period of time than the corresponding solution dissolved in styrene. For example, 60% dissolved in methyl methacrylate prepared in Example 5, when the polyurethane polymethacrylate solution was left in an amber glass bottle at ambient temperature, became gel after 4 weeks. In comparison, 60% of the polyurethane polymethacrylate solution prepared in Example 6, prepared in Example 6, took less than 24 hours to gel when left under the same conditions.

TABLE 1

Example 8

Polyurethane polyacrylate resins derived from ethyl acrylate and 'Suprasek' DND upon 2-high registration are i) 2-hydroxy ethyl acrylics containing 400 ppm paramethoxyphenol instead of 2-gkdlemdhrtldpxlf methacrylate. Similar to the method used in Example 5, except that the rate (178.5 g) and ii) 238.5 g of methyl acrylate are used, the solution is prepared in methyl methacrylate. The product was a brown solution (viscosity 75 centipoise) in methacrylate in which the weight ratio of polyurethane polyacrylate contained 60%.

Example 9

For comparison, polyurethane acrylate resins derived from 2-hydroxyethyl acrylate and 'Suprasek' DND were prepared as solutions in styrene.

The procedure is the same as the fixation described in Example 8, except that styrene (238.5 g) containing 10-20 ppm tert-butyl catechol is used instead of methyl methacrylate.

The product was a brown solution dissolved in styrene containing 60% by weight of polyurethane polyacrylate.

Example 10

Samples of the polyurethane polyacrylate resin solution prepared in Example 8 were diluted with methyl methacrylate to prepare 50%, 40% and 30% resin solutions.

Similarly, the polyurethane polyacrylate resin sample prepared in Example 9 was diluted with styrene (containing 10-20 ppm of tert-butyl catechol) to prepare 50%, 40% and 30% resin solutions. .

The polymerization of these solutions was shown in Tables II and III, as described in Example 7, with characteristics, namely gel time, time from gel to peak and peak temperature. In all cases, the bath temperature is 21 ° C.

TABLE 2

TABLE 3

Example 11

This example presents a method for producing glass fibers and copolymer plates by a resin injection molding method. The resins used are 2-hydroxyethylmethacrylate and polyuphetane polymethacrylate derived from 'Suprasek' DND. This resin is prepared as a solution in methyl methacrylate by the method described in Example 1. The solution was diluted with methyl methacrylate, resulting in a solution containing 30% resin relative to methyl methacrylate and the resin. Alumina trihydrate was dispersed in the diluent solution to produce a dispersion feed containing 50 alumina trihydrate per 50 dilutions.

3.2 mm glass and copolymer plates are prepared as follows.

Three layers of cut strand glass fiber mat (450 g / m 2) were placed between nickel plates (20 cm x 20 x 32 mm), and the mold was sealed using 3.2 mm silicon rubber as a gasket to fill the space. .

Benzoyl peroxide (1.5%) and N, N-dimethyl-para-toluidine (0.5%) were added to the dispersion feed described above and pumped into the mold at 20 ° C. The time required to fill the mold was 30 seconds.

After the mold was filled, it gelled in 110 seconds and the exothermic peak reached 205 seconds after the mold was filled. The rigid plate was demolded 210 seconds after the mold was filled. Suitable compositions of the plates are 30% glass fiber, 35% alumina trihydrate and 35% resin and methyl methacrylate copolymer. The bending strength of the plate was 175 MN / m 2, and the bending was measured with a length-to-depth ratio of 20: 1, and the result was 9 × 10 ⁹ / m 2.

Example 12

This example demonstrates the efficacy of poly (methyl metaacrylate) when reducing in-mold shrinkage.

A solution of polyurethane acrylate resin derived from 2-hydroxyethyl methacrylate and 'Suprasek' DND in methyl methacrylate was prepared by the method described in Example 1. The solution is diluted with methyl methacrylate to form a solvent containing 30% of the resin in methyl methacrylate and in the resin. 5.0 g of poly (methyl methacrylate) (Diakon, SG156: 'Diaco' is a trademark) was added to 50 g of the above solution, shaken at 40-50 ° C. to dissolve, and a clear solution (viscosity 33) Centipoise). To this clear solution, 50 g of alumina trihydrate (2-50 micron particle size) coated by shaking and easily sprayed with silane was added. The viscosity of this dispersion was 129 centipoise. The density of the dispersion at 20 ° C. was 1.420 g / ml. (Determined using relative bottle density).

Benzoyl peroxide (0.75 g) was dissolved in the dispersion, and then N, N-dimethyl-P-toluidine (10.15 g) was dissolved, and the product was quickly injected into a mold settled in a water bath maintained at 60 ° C. It was. The mold consists of two 3 mm thick glass plates, separated by 4 mm thick gaskets. The temperature of the polymerization dispersion was controlled by a thermometer, and the time to the highest point was 105 seconds. When the product after polymerization was removed from the mold, its density was found to be 1.440 g / ml (determined by weight in air and in water at 20 ° C).

The volume reduction due to polymerization is calculated from the following equation.

V / 100 = (d ₂ -d ₁ ) / d ₂

Food,

V is volumetric shrinkage expressed in ml per 100 ml dispersion

d ₁ is the dispersion density (g / ml)

d ₂ is the density of the product, demolded (g / ml)

The volumetric shrinkage is therefore V = 100 (1.440-1.420) = 1.39 ml / 100ml

The procedure for comparison is repeated except that the poly (methyl methacrylate) is omitted.

The peak time was 118 seconds. The density of the initial dispersion is 1.432 g / ml and the product density at the time of demoulding is 1.548 g / ml. So the volumetric shrinkage is V = 100 (1.584-1.432) /1.584 = 9.6ml / 100ml

Example 13

The structure of the mold is a pair of rectangular iron plates separated by 3 mm thick silicone rubber, which is a gasket, each having a thickness of 5 mm. The dimension of the mold cavity is 15 mm x 11 mm x 3 mm. The mold is immersed in a water weight of 20 ° C.

Solutions in methyl methacrylate of 2-hydroxyethyl methacrylate and polyurethane polymethacrylate resins derived from 'Suprasek' DND are prepared as described in Example 5. A portion of the solution is diluted with methyl methacrylate to prepare a test solution containing 60%, 50% and 40% resin, respectively.

The polymerization is carried out by taking 60 g of the test solution and dividing each into two. In one portion 0.9 g of dibenzoyl peroxide is added and in the other portion 0.3 g of N, N-dimethyl-P-toluidine. After temperature control to 20 ° C., the two parts are mixed, shaken thoroughly and immediately injected into the mold. Note the time at the peak temperature and quickly demould the casting product at this stage. Immediately after removal of the mold, the hardness of the polymer sample is measured, and the hardness thereafter is measured at an interval up to 1 hour after the sample is prevented from ambient temperature (20-22 ° C.) and the start of injection of the mold.

Hardness was determined using a scaled Barcol hardness indicator to read 100 on glass (the higher the reading value, the harder the specimen).

The procedure for comparison is repeated using a solution of a resin such as that described in Example 6 dissolved in styrene. Dilute a portion of the solution with styrene to prepare a test solution containing 60%, 50% and 40% resin.

Table IV shows the polymerization characteristics (time to peak temperature and peak temperature), the time when the specimen was demoulded and the hardness immediately after demoulding. When this table compares with copolymer with styrene. This suggests that the hardness at the time of demolding the copolymer of methyl methacrylate and resin is very large.

TABLE 4

* Is too low for measurable.

At ambient temperature, the rate of hardness increase that is subsequently followed by demolding is shown in Table V. In this table, "concentration" represents the concentration of the polyurethane polymethacrylate resin in the resin and the comonomer solution, and 'MMA' represents methyl methacrylate. The time is measured from the beginning of injecting the solution into the mold.

TABLE 5

* Is measured immediately after breakout.

Claims (15)

The (a) unsaturated urethane compound is a hydroxyl group of hydroxyalkyl acrylate or methacrylate and (i) a polyisocyanate having no urethane group and having 2.0 or more isocyanate functional groups, or (ii) a hydroxyl group of diol or triol. Polyurethane polyacrylate or polymethacrylate resins derived as hydroxyalkyl acrylates or methacrylates by reaction of isocyanate groups such as urethane polyisocyanates having an isocyanate functional group of 2.0 or more, derived from the reaction of (B) A method of molding a plastic product by copolymerizing in a mold a vinyl monomer copolymerizable with an unsaturated urethane compound, which is methyl methacrylate as the vinyl monomer. The hydroxyalkyl acrylate according to claim 1, wherein the polyurethane polyacrylate or polymethacrylate resin is reacted by reaction of a hydroxyl group of hydroxyalkyl acrylate or methacrylate with an isocyanate group of polymethylene polyphenyl polyisocyanate. Or methacrylate derived. The method of claim 1, wherein the polyurethane polyacrylate or polymethacrylate resin has at least 2.0 isocyanate functional groups by reaction of aliphatic diols or triols with polyisocyanates and is derived from polyurethane polyisocyanates derived from polyisocyanates. How. The method of claim 1, wherein the diol is a glycol of structure HO-Q-OH wherein Q is alkylene or polyalkylene ether radicals. The method of claim 1 wherein the diol is dihydric phenol or bis-phenol. The method of claim 1 wherein the triol is glycol or trimethylolpropane or an ethoxylated or propoxylated derivative thereof. The method of claim 1 wherein the polyisocyanate reacted with the diol or triol is polymethylene polyphenyl polyisocyanate. The process of claim 1, wherein the hydroxyalkyl acrylate or methacrylate hydroxyalkyl group contains from 2 to 4 carbon atoms. The process according to claim 1, wherein the proportion of the resin of the polyurethane polyacrylate and / or the polymethacrylate is 10-90 parts per 100 parts by weight of the mentioned resin and methyl methacrylate. The process according to claim 9, wherein the proportion of the resins mentioned is 25 to 50 parts per 100 parts by weight of methyl methacrylate and the resins mentioned. The method of claim 1 wherein the mixture to be polymerized comprises an organic polymer. The method of claim 11, wherein the organic polymer is poly (methyl methacrylate). The method of claim 11, wherein the proportion of organic polymer is 1-25 parts per 100 parts by weight of methyl methacrylate and polyurethane acrylate and / or methacrylate resin. The process of claim 1 wherein the mixture to be polymerized comprises an inorganic filler. The method of claim 14, wherein the filler consists of glass fibers.