JPS60245609A - Curable composition of improved flow - Google Patents

Abstract

PURPOSE:The titled composition with a viscosity reduced without causing its separation into components and adversely affecting its curability, prepared by adding a radical polymerization initiator to an inorganic filler-containing (meth) acrylate syrup to which at least one specified compound is added and agitating the mixture. CONSTITUTION:The titled composition is obtained by adding a radical polymerization initiator to a mixture whose viscosity is reduced to 30-200p (at 20 deg.C) by adding 0.05-2pts.wt. viscosity reducing agent comprising at least one compound of formula I, II, or III (wherein m is 1-2, n is 1-20, R3 is an 8-20C alkyl, and R1-2 are each R3 or a monoalkylphenol having an 8-20C alkyl) to 100pts.wt. inorganic filler-containing syrup formed by mixing 10-60wt% methacrylic syrup comprising methyl methacrylate and, optionally, a vinyl monomer copolymerizable therewith with 90-40wt% inorganic filler of a particle diameter of 1-50mu, and homogeneously agitating the resulting mixture. This composition is poured into a suitable mold and, after deaeration, cured by polymerization at room temperature-90 deg.C and, if necessary, heat-treated at 100 deg.C or above to obtain a cured casting excellent in appearance, hardness, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a curable methacrylic composition containing an inorganic filler with improved flowability.

Conventionally, cured resin products containing inorganic fillers have been widely used as artificial marble for sanitary wear such as bathroom vanities and kitchen counters, but these use unsaturated polyester resins or epoxy resins as matrix resins. This is common, and as an artificial marble, it cannot help but feel that it is modern in terms of appearance and physical properties such as weather resistance. In recent years, with the trend toward higher quality sanitary wear such as system kitchens, methacrylic resin has come to be used as a matrix resin, and its external hardness and thermal properties due to its outstanding transparency match the required performance. It is being evaluated as the most suitable artificial marble, and there are many patents related to artificial marble using methacrylic resin as a matrix. 55-2
No. 1776), method of adding silica (Japanese Patent Application Laid-open No. 51-5
383, JP-A-56-4611) or a method of adding other inorganic fillers (JP-A-54-103)
No. 94) etc. are disclosed. All of these require the addition of larger amounts of inorganic fillers to provide flame retardancy, improve hardness, improve appearance characteristics, and reduce costs, and finer particle sizes are used. There is. However, increasing the amount of inorganic filler and making the particle size finer will not only significantly increase the viscosity of the mixture with methacrylic silica, making it impossible to pour it into a mold, but also cause defoaming of the air contained in the mixture. At present, the amount of inorganic filler and particle size must be limited because it is difficult to obtain a good cast product. Furthermore, even if the viscosity of the methacrylic silica is lowered in order to prevent these drawbacks, not only will the fluidity not be as good as expected, but the inorganic filler and the methacrylic silica will separate, making it impossible to obtain a uniformly cast product. I can't do it.

As a result of research conducted by Nagisa et al. to overcome the above-mentioned drawbacks,
It has been shown that by adding a specific compound, the viscosity of the mixture can be lowered without causing separation between the inorganic filler and the silica, and without affecting the curability, and the desired fluidity can be obtained. Heading: The present invention has been completed.

That is, the present invention provides a method for polymerizing an inorganic filler-containing silica consisting of 10 to 60% by weight of methacrylic silica containing methyl tutaacrylate as a main monomer and 90 to 40% by weight of an inorganic filler in the presence of a radical polymerization initiator. , the following general formula (A
, )~(C)(A) (R+ + CHt CHt 0 )n % P (O
)I)s mR2÷CH, CHt 0s CCHtS
O3Na (B)1 (OHhm 0 0H CH.

At least 1 at O, 05-2. This is a curable composition with improved fluidity, characterized in that 1 part of O is added and the viscosity of the mixture is 30 to 2'OO voids (25°C).

In the present invention, the methacrylic silica is a monomer formed by polymerizing methyl methacrylate alone or a mixture of methyl methacrylate as the main monomer and a copolymerizable vinyl monomer in the presence of a polymerization initiator. Rather than dissolving a polymer or a methacrylic resin with the above monomer mixture containing methyl methacrylate as the main monomer, it is possible to use any method such as a filtration polymer and a monofilament polymer.
Among these, those having an intrinsic viscosity of 0.5 to 10 poise at 25°C are suitable. The copolymerizable vinyl monomers mentioned here include monofunctional monomers such as acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, vinyl cyanide, aromatic vinyl, divinylbenzene, allyl acrylate, There are polyfunctional monomers such as allyl methacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, trimethylolpropane triacrylate, and trimethylolpropane triacrylate.

The inorganic filler used in the present invention and 1. Examples include aluminum hydroxide, alumina, calcium carbonate, glue, magnesium hydroxide, magnesium oxide, titanium oxide, barium sulfate, mica, clay, and talc. , magnesium hydroxide, and other water supplies are preferred, and in terms of hardness and hot water resistance, alumina and silica are preferred. The amount of these inorganic fillers added is 40 to 90% by weight, preferably 50 to 80% by weight, based on the inorganic filler-containing silica, and if it is less than 40% by weight, the resin and filler will separate. Judging from the appearance of the resulting cast product, it is considered to be at a modern level as an artificial marble, and if it exceeds 90 tm, it is impossible to uniformly mix it even if any viscosity reducing agent is used in the present invention. The strength of the cast product is also significantly reduced, which is preferable. In addition, the particle size of these fillers affects the viscosity of the mixture with shirasoge, the separation from shirasoge due to settling of the filler, and the surface gloss and uniformity of the cast product.
0 μ is appropriate.

Further, the viscosity reducing agent of the present invention is the following compounds (A) to (C) having ethylenezo and recall chains.

R2(-CHtCH,0-)-C-CH2SO3Na
(B) 1 0 0H CH3 C-C=CHt (C) 1 In the compounds of the above general formulas (A) to (C), the substituent R
, , R, , R, has no effect if the number of carbon atoms is less than 8 or exceeds 20.

Conventionally, when the above-mentioned viscosity reducing agent is not used, the upper limit of the amount of inorganic filler added is about 70 M, no matter how much the viscosity of the thin material is reduced, and if this value is exceeded, the uniformity of the inorganic filler and the shirasoge becomes uniform. Mixing is impossible and pouring into a mold is very complicated, and it is currently impossible to add 70 to 90% by weight of an inorganic filler in practice. However, by adding the viscosity reducing agent of the present invention, the viscosity of the system is reduced even at a high content of inorganic filler, making uniform mixing possible. This viscosity reducing agent does not have the effect of lowering the viscosity of Shirasoge even when added to Shirasoge, and it only shows its effect in 7 lamps containing inorganic fillers, and has the characteristic that it does not depend on the type of inorganic filler. This effect is surprising. The amount of the viscosity reducing agent added is 0.05 to 2.0 parts by weight, more preferably 0.1 to 2.0 parts by weight, per 100 parts by weight of the inorganic filler-containing silica.
It is 1.0 part by weight. If the viscosity reducing agent is less than 0.05 parts by weight, the viscosity of the mixture will hardly change, and if it is added in excess of 2.0 parts by weight, no further viscosity reducing effect can be expected and the physical properties of the cured product will deteriorate. Undesirable. The viscosity of the curable composition containing these viscosity reducing agents is preferably 30 to 200 boids (B-type viscometer, 25°C), preferably 50 to 15 mm, from the viewpoint of ease of handling and uniform flowability into the mold.
It is 0 poise.

As the radical polymerization initiator in the present invention, known ones can be used, including diisoprobyl-oxydidicarbonate,
Bis-4-t-butylcyclohexyl peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, t-butylperoxydibiparate, lauroyl oxide, benzoyl peroxide,
t-Butyloxy(2-ethylhexanoate)
Kasa's J oxide initiator, 2.2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, 2.2'-azobis-2,4-dimethylvaleronitrile 7,2
/-Azo initiator such as azobisisobutyronitrile, benzoyl peroxide and N,N-di(2-hydroxyglobyl)-P-)luidine, NUN-), l f
A redox initiator is used in combination with a tertiary amine such as Luidine, N,N-dimethylaniline, etc., and a pressure and high temperature active initiator may also be used in combination (・.

The method of carrying out the present invention is to produce Shirabu by the method described above, add at least one compound of general formulas (A) to (C), an inorganic filler and a radical polymerization initiator, and mix thoroughly with stirring. The resulting curable composition is then poured into a suitable mold]2 and degassed.
Polymerization and curing at room temperature to 90℃, in some cases 100℃
A hardened cast product is obtained by heat treatment at a temperature above.

Further, the curable composition of the present invention may contain known plasticizers, lubricants, mold release agents, dyes and pigments, stabilizers, ultraviolet absorbers, etc., as necessary.

The present invention will be specifically described below with reference to Examples. The viscosity reducing agents used in the examples are each represented by the following abbreviations, and the viscosity of the curable composition is a value measured at 25° C. using a B-type viscometer.

Abbreviation: A2C,3H27-Gdan-(-CH2CH20S.P(OH)211OH!00H0CI(.

■ -C=CH.

Examples 1 to 7, Comparative Examples 1 to 4 Methyl methacrylate silica obtained by partial polymerization (2
Viscosity at 5°C (3 voids) K, viscosity reducing agent (A-1)
, silica (Crystalai FAA.

■Made by Tatsumori), alumina (A-42, manufactured by Showa Light Metal ■)
and aluminum hydroxide ()・idilite H-310
(manufactured by Showa Light Metal) were added in various proportions and mixed uniformly.

Next, 0.10 parts by weight of 2,2'-azobisisobutyronitrile was added to 100 parts by weight of the above lamp, and after degassing under reduced pressure, the mixture was poured into two glass cells and heated at 70°C for 3 hours. Subsequently, it was heated and cured at 120° C. for 2 hours. The viscosity of the curable composition and the evaluation results of the obtained casting plates are shown in Table 1, including comparative examples.

Examples 8 to 13, Comparative Examples 5 to 7 Methacrylic resin beads (Parabeads HR, manufactured by S Wagas Kagaku Kogyo ■) 20 Jutsuki 1%, methyl methacrylate 75% by weight, and trimethylolpropane trimethacrylate 5
For 3 parts by weight of Shirabu (viscosity 1.7 voids at 25°C) consisting of 3 parts by weight, the type and oak of the viscosity reducing agent were changed, and the warping force used in Example 1 was 52 parts by weight and 18 parts by weight of aluminum hydroxide. was added and mixed uniformly. Then benzoyl peroxide 0.06i4-1
% part, N,N-dimethyl-P-toluidine, 0.03 parts by weight was added, and after degassing under reduced pressure, the mixture was poured into two glass cells, heated at 25°C for 1 hour and 20 minutes, and then heated at 120°C for 2 hours. Cured by heating for hours. The viscosity of the curable composition and the evaluation results of the obtained casting plates are shown in Table 2, including comparative examples.

Examples 14 to 17, Comparative Example 8 to] 1 The same inorganic filler type was changed to 30 parts by weight of the same syrup and viscosity reducing agent B-1, 0, and 2 parts by weight as in Example 8, and 70 parts by weight were each used. of the mixture was added and mixed uniformly, and a casting plate was obtained in the same manner as in Example 8. The viscosity of the curable composition and the evaluation results of the obtained casting plates are shown in Table 3, including comparative examples.

Claims (1)

[Scope of Claims] fll 10 to 60% by weight of Metagril based sillage whose main monomer is methyl methacrylate and 90 to 40% by weight of an inorganic filler
When polymerizing the inorganic filler-containing silica in the presence of a radical polymerization initiator, the following general formulas (A) to (C) (R+ +CH2CHtO) + P ( OH)3 (
A,) nm --m 1] R2(-CH2CH20-)-C-CH2SO3Na
(B) 11°(OH)t m 0 0 HO CH. ■ Among the compounds represented by -C=CH2(C), at least is o, o s
~260 parts by weight was added to bring the viscosity of the mixture to between 30 and 200 parts by weight.
A curable composition with improved fluidity characterized by a void (25° C.).