JPH0569844B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a syrup composition for crosslinked methacrylic resin. More specifically, the present invention relates to a syrup composition for crosslinked methacrylic resin that provides a transparent crosslinked resin molded product with extremely low haze and excellent heat resistance. (Prior art) In general, methacrylic resins whose main component is methyl methacrylate are used in various fields such as lighting covers, automobile parts, signboards, decorative items, and miscellaneous goods due to their excellent weather resistance and outstanding transparency. However, since the methacrylic resin is a linear polymer, it has disadvantages in that it has insufficient heat resistance, solvent resistance, impact resistance, and surface hardness. For example, the limit for heat resistance is around 100℃,
At present, it is not possible to fully meet the demands of various fields that require heat resistance. For example, it cannot be used as a cover for a headlamp, which is an automobile part, and in the case of a tail lamp, the lamp itself has to be larger than conventional products, or the amount of heat generated due to increased illuminance has increased, and the walls have been made thinner to reduce costs. Improved heat resistance is required from both sides, and automobiles,
Methacrylic resin, which can withstand temperatures above the boiling point of water, is expected to expand into applications such as manufacturer covers for two-wheeled vehicles (motorcycles) and covers for water heaters that use solar thermal energy, as well as other parts whose temperature rises significantly under direct sunlight. is expected to be developed. Conventionally, for the purpose of improving the heat resistance of methacrylic resins, there has been a method of copolymerizing methyl methacrylate and α-methylstyrene (US Pat. No. 3,135,723),
Method for copolymerizing methyl methacrylate, α-methylstyrene, and maleic anhydride
A number of methods have been proposed, including a method of copolymerizing methyl methacrylate, α-methylstyrene and maleimide (Japanese Patent Application Laid-open No. 48-95490). However, although all of these methods improve heat resistance, the polymerization rate is extremely slow, the polymerization rate does not increase and a high polymerization rate cannot be obtained, or the polymer cannot be efficiently produced in a relatively short time. Even if it is obtained, it has both advantages and disadvantages, such as the strong coloration of the polymer and reduced transparency, weather resistance, surface hardness, mechanical strength, etc., and it is extremely difficult to produce it industrially, so it has not been put into practical use. This is the current situation. On the other hand, it is generally possible to improve heat resistance, solvent resistance, etc. by introducing a crosslinked structure into a linear polymer, but since the crosslinked polymer already has a three-dimensional structure, this crosslinked polymer It is not possible to mold the composite by injection molding, extrusion or transfer molding. Furthermore, when molding is performed by the cast polymerization method, voids, foaming, etc. are likely to occur, so that not only complex shapes cannot be molded, but the productivity is also low. In order to solve these drawbacks, in the methyl methacrylate syrup composition, 1 to 25% by weight of di(meth)acrylate of a linear aliphatic dihydric alcohol having 4 to 8 carbon atoms is added as a constituent component.
A composition containing
−167340). However, such compositions cannot be manufactured by injection molding, although cast polymerization can be used.
Since transfer molding methods and the like cannot be employed, the workability is poor, the shape of the molded product is naturally limited, and the dimensional stability is poor. (Problems to be Solved by the Invention) In order to solve the above-mentioned problems, the present inventors have formulated a specific amount of crosslinking agent into a syrup containing an alkyl methacrylate monomer or a polymer thereof. We proposed a methacrylic resin molding material made of a partially crosslinked gel polymer (Japanese Patent Application Laid-Open No. 60-202128
issue). However, when partially crosslinking polymerization is carried out by blending a crosslinking agent into the syrup, the affinity between the alkyl methacrylate polymer present in the syrup and the crosslinked polymer produced is usually insufficient, and as a result of the progress of polymerization. As a result of phase separation and generation of fine particles, the partially crosslinked gel-like polymer obtained becomes milky and opaque. This opaque partially crosslinked gel-like polymer regains transparency when it is completely solidified by heating and pressure molding, but it is not completely transparent and becomes a hazy polymer. Moreover, such polymers have the disadvantage that the difference in refractive index between the substrate and the precipitated particles increases due to temperature changes, resulting in increased haze. Therefore, an object of the present invention is to provide a novel syrup composition for crosslinked methacrylic resin. Another object of the present invention is to provide a syrup composition for crosslinked methacrylic resin that provides a transparent crosslinked resin molded article with extremely low haze and excellent heat resistance. (Means for Solving the Problems) These objects are (A) (a) a resin consisting of an alkyl methacrylate monomer or an α,β-ethylenically unsaturated monomer mixture containing alkyl methacrylate as a main component; (b) 0.05-0.8% by weight in raw materials
(B) an alkyl methacrylate syrup having a viscosity of 0.05 to 3000 poise (at 20°C) obtained by partially polymerizing a (meth)acrylate crosslinking agent; This is achieved by a syrup composition for crosslinked methacrylic resins comprising ~50% by weight of a crosslinking agent. (Function) The monomer used as the resin raw material (a) in the present invention includes alkyl methacrylate alone or a mixture of alkyl methacrylate and an α,β-ethylenically unsaturated monomer that can be copolymerized therewith. . In the case of such a monomer mixture, the alkyl methacrylate content is desirably 50 mol % or more, and preferably 60 mol % or more. As alkyl methacrylate,
Methyl methacrylate, ethyl methacrylate,
n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-
Examples include butyl methacrylate, tert-butyl methacrylate, and methyl methacrylate is particularly preferred. Examples of the copolymerizable monomer include alkyl methacrylates other than the alkyl methacrylate (e.g. methyl methacrylate) used as the main component (e.g. the above-mentioned alkyl methacrylates, 2-ethylhexyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, etc.), methyl acrylate, Ethyl acrylate, n-propyl acrylate, isopropyl acrylate,
Alkyl acrylates such as n-butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, cyclohexyl acrylate, 2
- hydroxyalkyl acrylates such as hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxy-3-chloropropyl acrylate,
Hydroxy alkyl methacrylates such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 2-hydroxy-3-chloropropyl methacrylate, acrylic acid, methacrylic acid, neodymium acrylate, acrylic Lead acid, acrylates such as boron acrylate, methacrylates such as neodymium methacrylate, lead methacrylate, boron methacrylate, vinyl chloride, vinyl acetate, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, styrene, α- Examples include methylstyrene, vinyltoluene, maleic anhydride, etc. In the present invention, the (meth)acrylate crosslinking agent (b) used for partial crosslinking of the syrup is a crosslinking agent having at least two (meth)acryloyl groups in the molecule. is propylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate (BD), 1,6-hexanediol dimethacrylate (HD), 1,3-butylene glycol dimethacrylate (BG), dimethylolethane dimethacrylate, 1 , 1-dimethylolpropane dimethacrylate, 2,2-dimethylolpropane dimethacrylate, trimethylolethane triacrylate, trimethylolethane trimethacrylate (TMET), trimethylolpropane triacrylate (A-TMPT), trimethylolpropane trimethacrylate (TMPT),
Tetramethylolmethane triacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethane dimethacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate (1G), diethylene glycol diacrylate (A-2G), diethylene glycol dimethacrylate (2G), Propylene glycol dimethacrylate (P-2G), neopentyl glycol diacrylate (A-NPG), neopentyl glycol dimethacrylate (NPGDM)
etc. can be mentioned. In addition, triethylene glycol dimethacrylate (3G), tetraethylene glycol dimethacrylate (4G), polyethylene glycol dimethacrylate (9 ethylene oxide repeating units) (9G), polyethylene glycol dimethacrylate (14 ethylene oxide repeating units) (14G) ), polyethylene glycol dimethacrylate (23 repeating ethylene oxide units) (23G), polypropylene glycol dimethacrylate (9 repeating propylene oxide units) (P-9G), 2,2'-bis (4
-methacryloxydiethoxyphenyl)propane, tetraethylene glycol diacrylate (A-4G), polyethylene glycol diacrylate (number of ethylene oxide repeating units: 9)
(A-9G), polyethylene glycol diacrylate (14 ethylene oxide repeating units)
(A-14G), 1,3-butylene glycol diacrylate (A-BG), 1,6-hexanediol diacrylate (A-HD), polypropylene glycol diacrylate (number of repeating propylene oxide units) (AP-9G) ), 2,2'-bis(4-acryloxypropyloxyphenyl)propane, 2,2'-bis(4-acryloxydiethoxyphenyl)propane, tetramethylolmethanetetraacrylate (A-TMMT), etc. be. The (meth)acrylate crosslinking agent (b) is
0.05 to 0.8% by weight based on the resin raw material (a),
Preferably 0.1-0.6% by weight, most preferably 0.1-0.6% by weight
It is mixed at 0.4% by weight and subjected to partial crosslinking polymerization.
That is, if the haze reduction effect is less than 0.05% by weight, the haze reduction effect is insufficient, while if it exceeds 0.8% by weight, a gel is rapidly generated as the polymerization progresses in the syrup production reaction, so that the haze reduction effect is insufficient. This is because you can only get syrup. In order to form a syrup from such a blend of resin raw material (a) and (meth)acrylate crosslinking agent (b), 30%
0.5-10 at a temperature of ~100℃, preferably 50-100℃
Viscosity of 0.05 to 3000 poise, preferably 0.2 to 1000 poise (measured at 20°C) by conducting the reaction for 1 to 5 hours and partially crosslinking polymerization.
of syrup is obtained. The polymerization degree of the polymer in this syrup is 1000 to 30000, preferably 3000 to 30000.
and its content is 3 to 30% by weight, preferably 3
~20% by weight. The polymerization initiator is the resin raw material (a) and (meth)
Based on the total amount of acrylate crosslinking agent (b)
0.0002-0.1% by weight, preferably 0.0005-0.05% by weight is used. Various types of polymerization initiators can be used, but if a low-temperature active polymerization initiator is used, it will be almost completely consumed in the syrup production reaction, so the polymerization initiator will remain in the final syrup composition. stability is increased. As the low-temperature active polymerization initiator, peroxide and azo compound radical polymerization initiators having a decomposition temperature of 50° C. or lower to obtain a half-life of 10 hours, for example, are preferable. In order to improve the storage stability of this syrup, a low temperature active polymerization initiator is used in the polymerization process to obtain the syrup.
Since it is preferable for the decomposition to disappear as much as possible, the decomposition temperature is preferably 26 to 45°C, particularly preferably 26 to 41°C. Examples of such low-temperature active polymerization initiators include ()acetylcyclohexylsulfonyl peroxide, isobutyryl peroxide, cumyl peroxyneodecanoate, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, and Myristyl peroxydicarbonate, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), ()
Di-(2-ethoxyethyl) peroxydicarbonate, di-(methoxyisopropyl) peroxydicarbonate, di-(2-ethylhexyl)
peroxydicarbonate, ()di-(3-methyl-3-methoxybutyl)peroxydicarbonate, t-butyl peroxyneodecanoate,
2,2'-azobis(2,4-dimethylvaleronitrile), etc., and among these, compounds belonging to the groups () and () are preferred, and compounds belonging to the group () are particularly preferred. . In the partial crosslinking polymerization reaction for producing syrup, a chain transfer agent may be added if necessary.
As a chain transfer agent, methyl mercaptan, ethyl mercaptan, isopropyl mercapan, n
-butylmercaptan, t-butylmercaptan, n-hexylmercaptan, n-octylmercaptan, n-dodecylmercaptan, ethylthioglycolate, mercaptoethanol, thio-β-naphthol, thiophenol, and the like. The amount used is 0.005 to 0.5 based on the total amount of resin raw material (a) and (meth)acrylate crosslinking agent (b).
% by weight, preferably 0.01-0.5% by weight. The alkyl methacrylate syrup (A) thus obtained contains 5 to 50% by weight, preferably 5 to 40% by weight, most preferably 5 to 40% by weight, based on the total amount of the syrup (A) and crosslinking agent (B). By blending 5 to 30% by weight of the crosslinking agent (B), the desired syrup composition for crosslinked methacrylic resin is obtained. The crosslinking agent (B) to be added to the syrup (A) must be a (meth)acrylate crosslinking agent, and in particular, it must have at least two (meth)acryloyl groups in the molecule, and the above-mentioned A monomer having 10 or less atoms in the main chain existing between (meth)acryloyl groups, more preferably a monomer with the following formula - MA-O-(CH ₂ ) _o -O-MA () (However, the formula medium, n is an integer from 3 to 6,
MA represents a methacryloyl group. )

[In the formula, R ¹ is H, CH ₃ , C ₂ H ₅ or
CH ₂ OH group, R ² is H, CH ₃ ,

[Formula] (where R ⁴ represents H or CH ₃ group) or CH ₂ OH group, R ³ represents H or CH ₃ group, and R ¹ , R ² and R ³ are not hydrogen at the same time. (M)A represents a methacryloyl group or an acryloyl group. ]

[Chemical formula] (In the formula, R ⁵ is H or CH ₃ ,
Further, n is 1 or 2. ) is a monomer represented by Specific examples of these monomers include propylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate (BD), 1,
6-hexanediol dimethacrylate (HD),
1,3-butylene glycol dimethacrylate (BG), dimethylolethane dimethacrylate,
1,1-dimethylolpropane dimethacrylate, 2,2-dimethylolpropane dimethacrylate, trimethylolethane triacrylate,
Trimethylolethane trimethacrylate (TMET), trimethylolpropane triacrylate (A-TMPT), trimethylolpropane trimethacrylate (TMPT), tetramethylolmethane triacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethane dimethacrylate, ethylene glycol Diacrylate, ethylene glycol dimethacrylate (1G), diethylene glycol diacrylate (A-2G), diethylene glycol dimethacrylate (2G), dipropylene glycol dimethacrylate (P-2G), neopentyl glycol diacrylate (A-NPG), Neo Examples include pentyl glycol dimethacrylate (NPGDM). These crosslinking agents (B) include 1G, 2G, BG, HD, NPGDM, P-2G,
TMPT, TMET and A-TMPT are preferred. The syrup composition obtained in this way includes:
A polymerization initiator and other additives are blended as necessary and subjected to polymerization to obtain a crosslinked polymer.
Polymerization is usually carried out by casting polymerization, which is carried out to form a predetermined shape at the same time as the polymerization. Polymerization may be carried out simultaneously with molding by heating and pressurizing by a molding method, transfer molding method, compression molding method, or the like. Cast polymerization is usually carried out at a temperature of 30 to 130°C, preferably 40 to 130°C.
It is carried out at a temperature of 130° C. for 2 to 10 hours, preferably 3 to 10 hours. The polymerization initiator is a syrup (A) and a crosslinking agent (B).
0.005-0.5% by weight, preferably based on the total amount of
Used at 0.01-0.5% by weight. As the polymerization initiator, in addition to the above-mentioned low-temperature active polymerization initiator, the following polymerization initiators are used. Examples of such polymerization initiators include ()
t-Butylcumyl peroxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, p-menthane hydroperoxide, 2,5-dimethyl-2,5-di-
(t-butylperoxy)hexyne-3,1,1,
3,3-tetramethylbutyl hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide,
1,1,2,2-tetraphenyl-1,2-ethanediol, ()1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butyl peroxy) cyclohexane, t-butyl peroxymale acid, t-butyl peroxylaurate, t
-Butylperoxy-3,5,5-trimethylhexanoate, cyclohexanone peroxide, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,2- Bis(t-butylperoxy)octane, t-butylperoxyacetate, 2,2-bis(t-butylperoxy)butane, t-butylperoxybenzoate, n-butyl-4,4-bis(t- butylperoxy)valerate, di-t-butyldiperoxyisophthalate, methyl ethyl ketone peroxide, α,α′-bis(t-butylperoxy-
m-isopropyl)benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, ()m-toluoyl peroxide, benzoyl peroxide,
t-Butyl peroxyisobutyrate, 2,3-
Dimethyl-2,3-diphenylbutane, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, stearoyl peroxide, propionyl peroxide, succinic acid, peroxide, acetyl peroxide, 1,1' azobis(cyclohexane- 1-Carbonitrile) () t-hexyl peroxy neohexanoate, t-butyl peroxy neohexanoate, 2,4-dichlorobenzoyl peroxide, t-hexyl peroxy pivalate, t-butyl peroxy pivalate barreto,
Examples include 3,5,5-trimethylhexanoyl peroxide. (Example) Next, the present invention will be explained in further detail by giving examples. Examples 1 to 5 0.2% by weight of NPGDM (b) and 0.002% by weight of cumyl peroxyneodeca as a polymerization initiator based on the total amount of methyl methacrylate (a) and neopentyl glycol dimethacrylate (NPGDM) (b) Methyl methacrylate to which PCND was added was reacted at a temperature of 60 DEG C. to prepare a methyl methacrylate syrup (A) containing a partially crosslinked polymer having the degree of polymerization shown in Table 1. A syrup composition for a crosslinked methacrylic resin was prepared by adding 20% by weight of NPGDM (B) to the total amount of the syrup (A) and NPGDM (B). To this syrup composition, 0.15% by weight of t-butyl peroxyisobutyrate (PBIB) was added as a polymerization initiator, and cast polymerization was carried out under the conditions shown in Table 1. A crosslinked polymethyl methacrylate plate of m was obtained. When the load deflection temperature (HDT) and haze value at 23°C and 130°C were measured for this plate, the results shown in Table 1 were obtained. Note that the deflection temperature under load was measured according to JIS K 7207 (bending stress 18.6 Kg/cm ² ). Further, the haze value was measured according to JIS K 7105. Comparative Examples 1 to 5 0.002% by weight of 2,2'-azobisisobutyronitrile (AIBN) was added as a polymerization initiator to methyl methacrylate and reacted at a temperature of 95°C to produce the polymerization shown in Table 1. A methyl methacrylate syrup was prepared containing a linear polymer of 50%. A syrup composition for a crosslinked methacrylic resin was prepared by adding 20% by weight of NPGDM (B) to the total amount of the syrup (A) and NPGDM (B). To this syrup composition, 0.15% by weight of t-butyl peroxyisobutyrate was added as a polymerization initiator, and cast polymerization was carried out at a temperature of 60°C for 3 hours and then at a temperature of 130°C for 2 hours. A cross-linked polymethyl methacrylate plate having a thickness of 5 m/m was obtained. When the same test as in Example 1 was conducted on this board,
The results shown in Table 1 were obtained. Examples 6-10 Using 0.1% by weight of trimethylolpropane trimethacrylate (TMPT) as (b), the syrup (A) and the methyl methacrylate syrup obtained in the same manner as in Examples 1-5 were added. 1,3
-Butylene glycol dimethacrylate (BG)
A syrup composition for crosslinked methacrylic resin was prepared by adding 20% by weight of BG (B) based on the total amount of BG (B). To this syrup composition, 0.15% by weight of PBIB was added as a polymerization initiator, and cast polymerization was carried out at a temperature of 60°C for 3 hours and then at a temperature of 130°C for 2 hours. A crosslinked polymethyl methacrylate plate was obtained. Example 1 about this board
When similar tests were conducted, the results shown in Table 1 were obtained. Comparative Examples 6 to 10 A syrup composition was prepared by adding the same crosslinking agent (B) as in Example 6 to the methyl methacrylate syrup obtained in the same manner as in Comparative Examples 1 to 5, and the syrup composition was prepared under the same conditions. When the same tests as in Example 1 were carried out on the plate obtained by polymerization, the results shown in Table 1 were obtained. Examples 11-15 Using 0.1% by weight of NPGDM as (b), methyl methacrylate syrup obtained in the same manner as Examples 1-5 was added with the syrup (A) and 1,6
-Hexanediol dimethacrylate (HD)
A syrup composition for crosslinked methacrylic resin was prepared by adding HD (B) in an amount of 20% by weight based on the total amount of HD (B). To this syrup composition, 0.15% by weight of PBIB was added as a polymerization initiator, and cast polymerization was carried out at a temperature of 60°C for 3 hours and then at a temperature of 130°C for 2 hours. A crosslinked polymethyl methacrylate plate was obtained. Example 1 about this board
When similar tests were conducted, the results shown in Table 1 were obtained. Comparative Examples 11 to 15 A syrup composition was prepared by adding the same crosslinking agent (B) as in Example 11 to the methyl methacrylate syrup obtained in Comparative Examples 6 to 10, and polymerization was carried out under the same conditions. When the same test as in Example 11 was conducted on the obtained plate, the results shown in Table 1 were obtained. Examples 16-20 Using 0.2% by weight of TMPT as (b), methyl methacrylate syrup obtained in the same manner as in Examples 1-5 was added with the syrup (A) and trimethylolpropane trimethacrylate (TMPT). )
20% by weight of TMPT (B) based on the total amount with (B)
A syrup composition for crosslinked methacrylic resin was prepared. To this syrup composition, 0.15% by weight of PBIB was added as a polymerization initiator, and the mixture was heated at 60°C.
for 3 hours at a temperature of
Cast polymerization was performed to obtain a crosslinked polymethyl methacrylate plate with a thickness of 5 m/m. When this board was subjected to the same test as in Example 1, the results shown in Table 1 were obtained. Comparative Examples 16-20 A syrup composition was prepared by adding the same crosslinking agent (B) as in Example 16 to the methyl methacrylate syrup obtained in Comparative Examples 6-10, and polymerization was carried out under the same conditions. When the same test as in Example 16 was conducted on the obtained plate, the results shown in Table 1 were obtained. Examples 21-25 Using 0.3% by weight of ethylene glycol dimethacrylate (1G) as (b), Examples 1-5
To the methyl methacrylate syrup obtained in the same manner as above, 20% by weight of TMET (B) was added to the total amount of the syrup (A) and trimethylolethane trimethacrylate (TMET) (B). A syrup composition for crosslinked methacrylic resin was prepared. To this syrup composition, 0.15% by weight of PBIB was added as a polymerization initiator, and 3% by weight was added at a temperature of 60°C.
Cast polymerization was carried out at a temperature of 130° C. for 2 hours to obtain a crosslinked polymethyl methacrylate plate having a thickness of 5 m/m. When this board was subjected to the same test as in Example 1, the results shown in Table 1 were obtained. Comparative Examples 21 to 25 A syrup composition was prepared by adding the same crosslinking agent (B) as in Example 21 to the methyl methacrylate syrup obtained in Comparative Examples 6 to 10, and polymerization was carried out under the same conditions. When the same test as in Example 21 was conducted on the obtained plate, the results shown in Table 1 were obtained. Examples 26-30 Using 0.5% by weight of 1G as (b), Example 1
20% by weight of 1G (B) based on the total amount of the syrup (A) and etrene glycol dimethacrylate (1G) (B) was added to the methyl methacrylate syrup obtained in the same manner as in 5. A syrup composition for crosslinked methacrylic resin was prepared. To this syrup composition, 0.15% by weight of PBIB was added as a polymerization initiator, and cast polymerization was carried out at a temperature of 60°C for 3 hours and then at a temperature of 130°C for 2 hours. A crosslinked polymethyl methacrylate plate was obtained. When this board was subjected to the same test as in Example 1, the results shown in Table 1 were obtained. Comparative Examples 26-30 A syrup composition was prepared by adding the same crosslinking agent (B) as in Example 26 to the methyl methacrylate syrup obtained in Comparative Examples 6-10, and polymerization was carried out under the same conditions. When the same test as in Example 26 was conducted on the obtained plate, the results shown in Table 1 were obtained. Examples 31-35 Using 0.4% by weight of NPGDM as (b), the syrup (A) and trimethylolpropane triacrylate (A) were added to the methyl methacrylate syrup obtained in the same manner as in Examples 1-5. −
TMPT) 20% by weight of A- based on the total amount with (B)
A syrup composition for crosslinked methacrylic resin was prepared by adding TMPT (B). To this syrup composition, 0.15% by weight of PBIB was added as a polymerization initiator, and cast polymerization was carried out at a temperature of 60°C for 3 hours and then at a temperature of 130°C for 2 hours. A crosslinked polymethyl methacrylate plate was obtained. When this board was subjected to the same test as in Example 1, the results shown in Table 1 were obtained. Comparative Examples 31 to 35 A syrup composition was prepared by adding the same crosslinking agent (B) as in Example 31 to the methyl methacrylate syrup obtained in Comparative Examples 6 to 10, and polymerization was carried out under the same conditions. When the same test as in Example 31 was conducted on the obtained plate, the results shown in Table 1 were obtained. Examples 36-55 Using 0.2% by weight of 1,6-hexanediol diacrylate (A-HD) as (b), the same was added to the methyl methacrylate syrup obtained in the same manner as in Examples 1-5. A syrup composition for crosslinked methacrylic resin was prepared by blending NPGDM (B) in the amount shown in Table 2 with syrup (A). 0.15% by weight of polymerization initiator based on this syrup composition
of PBIB and incubated at a temperature of 60°C for 3 hours.
Cast polymerization is performed at a temperature of 130℃ for 2 hours to obtain a plate thickness.
A 5 m/m crosslinked polymethyl methacrylate plate was obtained. When this plate was subjected to the same test as in Example 1, the results shown in Table 2 were obtained. Comparative Examples 36 to 50 A syrup composition for crosslinked methacrylic resin was prepared by blending the methyl methacrylate syrup obtained in Comparative Examples 6 to 10 with the amount of crosslinking agent (B) shown in Table 2. Polymerization was carried out under the same conditions as in Example 36, and the obtained plate was subjected to the same tests as in Example 1, and the results shown in Table 2 were obtained. Examples 56-61 Methyl methacrylate (a) and NPGDM (b)
A methyl methacrylate mixture to which 0.2% by weight of NPGDM (b), 0.02% by weight of PCND as a polymerization initiator, and a chain transfer agent of the type and proportion shown in Table 3 are added to the total amount of the methyl methacrylate is reacted at a predetermined temperature. Methyl methacrylate syrup containing partially crosslinked polymers having the degree of polymerization shown in Table 3 was prepared. A syrup composition for a crosslinked methacrylic resin was prepared by adding 20% by weight of the crosslinking agent (B) based on the total amount of the syrup (A) and the crosslinking agent (B) shown in Table 3. To this syrup composition, 0.15% by weight of PBIB was added as a polymerization initiator, and cast polymerization was carried out under the conditions shown in Table 3 to obtain a crosslinked polymethyl methacrylate plate having a thickness of 5 m/m. When this board was subjected to the same test as in Example 1, the results shown in Table 3 were obtained.

【table】

【table】

【table】

【table】

【table】

[Table] (Effects of the Invention) As described above, the present invention provides (A) (a) an alkyl methacrylate monomer or an α,β-ethylenically unsaturated monomer mixture containing alkyl methacrylate as a main component; (b) 0.05~
An alkyl methacrylate syrup having a viscosity of 0.05 to 3000 poise (at 20°C) obtained by blending and partially polymerizing 0.8% by weight of a (meth)acrylate crosslinking agent, and (B) the total amount of the syrup and crosslinking agent. Since this is a syrup composition for a crosslinked methacrylic resin comprising 5 to 50% by weight of a crosslinking agent based on the alkyl methacrylate syrup, the partially crosslinked polymer in the alkyl methacrylate syrup and the crosslinking agent (B ) has the advantage that haze generation is extremely low, and the effect is particularly remarkable at high temperatures. Furthermore, since the molded product obtained by polymerizing the syrup composition is a crosslinked polymer, it has high heat resistance and mechanical strength;
Moreover, it has excellent transparency.

Claims (1)

[Scope of Claims] 1 (A) (a) A resin raw material consisting of an alkyl methacrylate monomer or a mixture of α, β-ethylenically unsaturated monomers containing alkyl methacrylate as a main component, and (b) 0.05 to 0.8 weight. % (meta)
an alkyl methacrylate syrup having a viscosity of 0.05 to 3000 poise (at 20°C) obtained by blending and partially polymerizing an acrylate crosslinking agent; (B) 5 to 50 poise based on the total amount of the syrup and crosslinking agent;
A syrup composition for a crosslinked methacrylic resin, comprising a crosslinking agent of % by weight. 2 The viscosity of the alkyl methacrylate syrup is
The syrup composition according to claim 1, which has a poise of 0.2 to 1000 poise. 3. The syrup composition according to claim 1 or 2, wherein the crosslinking agent (B) is 5 to 40% by weight based on the total amount of the syrup (A) and the crosslinking agent (B). 4. The (meth)acrylate crosslinking agent (b) according to claim 1 or 2, wherein the (meth)acrylate crosslinking agent (b) is a (meth)acrylate crosslinking agent having at least two (meth)acryloyl groups in the molecule. syrup composition. 5. Claim 1, wherein the crosslinking agent (B) has at least two (meth)acryloyl groups in the molecule, and the number of atoms in the main chain existing between the (meth)acryloyl groups is 10 or less. The syrup composition according to any one of items 1 to 3. 6 The crosslinking agent (B) has the general formula MA-O(-CH ₂ )- _o O-MA () (wherein, MA is a methacryloyl group, and n is an integer from 3 to 6), General Formula [In the formula, (M) A is an acryloyl group or a methacryloyl group, R ¹ is H, CH ₃ , C ₂ H ₅ or CH ₂ OH, R ² is H, CH ₃ ,
[Formula] (where R ⁴ is H or CH ₃ ) or CH ₂ OH, R ³ is H or
CH ₃ and R ¹ , R ² and R ³ are not H at the same time. ], and the general formula [formula] (wherein, R ⁵ is H or CH ₃ ,
The syrup composition according to any one of claims 1 to 5, which is at least one compound having a formula selected from the group consisting of n = 1 or 2. 7. The syrup composition according to any one of claims 1 to 6, wherein the alkyl methacrylate is methyl methacrylate.