JPS60226510A - Production of methacrylic resin prepreg - Google Patents

Abstract

PURPOSE:To obtain the titled product, easily handleable, and quickly curable at a low molding temperature, by partially polymerizing methyl methacrylate thermally in the presence of a radical polymerization initiator of specific combination and a fibrous base material. CONSTITUTION:100pts.wt. monomer mixture consisting of (A) 60-100wt% methyl methacrylate and (B) 40-0wt% copolymerizable vinyl based monomer is polymerized thermally in the presence of (C) 0.01-3pts.wt. radical polymerization initiator, e.g. cumyl peroxide, having <=50 deg.C temperature at 10hr half-life and (D) 0.1-1pts.wt. radical polymerization initiator, e.g. benzoyl peroxide, having >=70 deg.C temperature at 10hr half-life and a fibrous base material to provide 40-60% polymerization ratio of the system and afford the aimed material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing methacrylic resin prepreg. Taking advantage of its excellent transparency and weather resistance, methacrylic resin is widely used in fields such as molding materials, outdoor applications as casting plates or extrusion plates, and optical fields. Molding materials mixed with fiber or mica, extruded plates, or cast plates coated with glass mat or glass cloth are known. However, among these, methacrylic resin casting boards coated with glass mats or glass cloth are widely used for lighting in arcades and recreational facilities, and as an alternative to tents that also serve as displays in the restaurant industry. Therefore, on the contrary, moldability was limited, and not only was it difficult to process into an arbitrary shape, but there were also defects in appearance such as wrinkles occurring at one bend or glass mat appearing on the resin surface. . Therefore, if it were possible to manufacture a methacrylic resin prepreg that is easy to mold and can be processed into any shape, it is clear that the applications would be further expanded. At present, it has hardly been put into practical use due to the difficulties in the manufacturing method, such as adjusting the amount of water, maintaining limited stability, shortening the molding time, and improving the polymerization rate of molded products. Thermosetting resins such as polyester resins, epoxy resins, and phenolic resins are commonly used as resins for prepregs, and polyamide resins and polysulfone resins are used as thermoplastic resins, but they all require organic solvents as diluents. Since it is used as a methacrylic resin, it is necessary to prevent deterioration of the working environment and treat volatile solvents, and although each has its own advantages depending on the purpose of use, it is inferior in transparency and weather resistance compared to methacrylic resin.

Therefore, it can be said that methacrylic resin prepreg is an ideal surface resin that has no problems in the working environment and is expected to be used in fields that take advantage of the inherent characteristics of methacrylic resin and the characteristics of prepreg.

The present inventors have conducted extensive research to overcome the above-mentioned drawbacks and difficulties, and have found that by selecting a radical polymerization initiator and polymerization temperature, handling is much easier than K100.
The present inventors have discovered that a methacrylic resin prepreg that cures in a short time at a relatively low molding temperature of ~150°C and provides good physical properties has been completed, and the present invention has been completed.

That is, the present invention is directed to radical polymerization with a 10-hour half-life temperature of 50°C or less for 100 parts by weight of a monomer mixture consisting of 60 to 100 parts by weight of methyl methacrylate and 40 to 0 parts by weight of a copolymerizable vinyl monomer. Initiator (A) 0.01~
When 0.3 parts by weight and 0.1 to 1.0 parts by weight of a radical polymerization initiator (B) with a 10-hour half-life temperature of 70°C or higher are added and polymerized by heating in the presence of a fiber base material, K. The present invention relates to a method for producing a methacrylic resin prepreg, characterized in that the polymerization rate of the system is 40 to 60%.

The copolymerizable vinyl monomers used in the present invention include methacrylic acid esters such as ethyl methacrylate, propyl methacrylate, butyl methacrylate, and cyclohexyl methacrylate, methyl acrylate, ethyl acrylate, and propyl acrylate. , acrylic esters such as butyl acrylate and 2-ethylhexyl acrylate, and styrene.

α-methylstyrene, p-methylstyrene, acrylonitrile, allyl methacrylate and the like can be used alone or in combination. The amount of the copolymerizable vinyl monomer added is preferably 40% by weight or less; if it exceeds 40% by weight, the polymerization behavior will change, making it impossible to obtain the desired polymerization rate, or polymerization may not be completed during molding. This is not preferable because the physical properties of the molded product deteriorate.

Allyl methacrylate is also used as a crosslinking monomer.

Allyl acrylate, ethylene glycol dimethacrylate, ethylene glycol diacrylate.

Polyethylene glycol dimethacrylates, polyethylene glycol diacrylates, divinylbenzene,
Trimethylolprono(trimethacrylate, trimethylolpropane triacrylate, etc.) may be used in an amount of 1% by weight or less.

The 10-hour half-life temperature of a radical polymerization initiator referred to below means that the amount of polymerization initiator in a benzene solvent is 1 at a constant temperature.
The temperature is 2 minutes IK at 0 hours.

As the radical polymerization initiator used in the present invention, known peroxide-based initiators and azo-based initiators can be used, but as the radical polymerization initiator (A) at a lower temperature, 1
0 hour half-life temperature is below 50℃.

More preferably, the temperature is 45°C or lower, such as di-3-methoxybutyl peroxydicarbonate, ') isobutyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, di-secadarybutyl peroxydicarbonate, di-n-propyl peroxydicarbonate, 2,4.4-trimethylpentyl peroxyhenoxy acetate, tert-butyl peroxy neodecanoate, cumyl peroxy neodecanoate, isobutyl peroxide, acetyl cyclohexyl sulfonyl peroxide, etc. Peroxide initiator, 2.2'-
7zobis-N, N-dimethylene isoptyramidine dihydrochloride, 2,2'-7zobis-4-methoxy-
An azo initiator such as 2,4-dimethylvaleronitrile can be used, and the amount of initiator is 0.01 to 0.3 parts by weight, more preferably 0.0 parts by weight based on 9 parts by weight of the monomer mixture.
If the amount is less than 0.01 part by weight, the polymerization time will be very long and it will not be economical, and the desired polymerization rate will not be reached. This is not preferred because it leads to induced decomposition of the initiator with a higher 10-hour half-life temperature than the one used in combination, making it impossible to terminate the polymerization.

As a higher temperature radical polymerization initiator (B), G@10 hour half-life temperature is 70°C or higher, more preferably 80 to 11°C.
For example, methyl ethyl ketone peroxide 0. Methyl isobutyl ketone peroxide, cyclohexanone peroxide.

Methylcyclohexanone ketone peroxide.

Dicumyl peroxide, tert-butyl cumyl peroxide, 2,5-dimethyl-2,5-diter-butyl peroxyhexane, 2,2-tert-butyl peroxybutane, tert-butyl peroxy acetate, ditertiary butyl peroxide Peroxide-based initiators such as butyl peroxyhexahydroterephthalate, ditertiary butyl peroxyazelate, benzoyl peroxide, or 1,1'-azobis-1-cyclohexane carbonitrile, 2-carbamol azoisoptylonitrile, 2. Azo initiators such as 2'-azobis-2,4,4-trimethylpentane can be used, and two or more types') #Jf14@L, -v"0"・lI#*JII
L-Cd$t, 0.0% per 100 parts by weight of the i-temperature mixture.
1 to 1.0 parts by weight, more preferably 0.2 to 0.6 parts by weight
If it is less than 0.1 part by weight, the polymerization rate during molding will not increase and the heat distortion temperature of the molded product will decrease, which is undesirable.

Furthermore, if the amount of initiator exceeds 1.0 parts by weight, foaming occurs during molding, making it impossible to obtain a product with a good appearance. If the 10-hour half-life temperature is less than 70°C, the initiator is likely to be induced to decompose at the polymerization temperature, and the storage stability of the prepreg will be reduced, which is not preferred.

Radical polymerization initiator (A) and (Bl) used in the present invention
During each 10-hour half-life temperature of (1)
It is necessary to satisfy the formula, TO-TA≧30 ・
・・・・・・・・・(1) TA: Radical polymerization initiator (A
) 10-hour half-life temperature (℃) TB: 10-hour half-life temperature (℃) of radical polymerization initiator (B) When TB-TA<30, high-temperature active initiator for polymerization from monomer mixture to prepreg Induced decomposition occurs, making it impossible to stop the polymerization, and preventing the desired polymerization rate from being obtained.
Furthermore, between the 10-hour half-life temperature and the polymerization temperature of the radical polymerization initiator (A) and (Bl), the following formula (2) and (
3) It is necessary to satisfy the formula TA ≦ 'rp ≦ TB -20...
・ (2) Tp ≦ 60 ・・・・・・・・・ (3
) TP: Polymerization temperature ('C) In formula (2), if TA >'rp, the polymerization time becomes very long, which is unfavorable from the viewpoint of productivity, and Tp > T.
In a-20, the radical polymerization initiator (B) decomposes and it becomes impossible to stop the polymerization, and the desired product cannot be obtained, so it is necessary to satisfy formula (2) as one polymerization temperature range. Also(
If 'rp>so in equation 3), even if the conditions of equation (2) are satisfied, the polymerization due to heat will cause an opening force and it will be difficult to stop the polymerization, making it impossible to obtain a predetermined polymerization rate, which is not preferable.

In the present invention, a fiber base material such as a cloth, mat, or nonwoven paper made of glass, mica, polyamide, or polyester is dipped or coated with a mixture solution that satisfies the above-mentioned conditions, and then heated and polymerized at a predetermined temperature. This invention relates to a method for obtaining a methacrylic resin prepreg as a partially polymerized product, and the fiber base material used here is not particularly limited.

The polymerization rate of the methacrylic resin prepreg in the present invention is 40~
60%, more preferably 45 to 55%, and when this range is satisfied, it is much easier to handle than masking both sides of the sheet with vinylon film, polyethylene film, etc.

Easy to cut with regular scissors or a utility knife.

The masking peel is in good condition. The molding conditions are 100-150°C, more preferably 120-140°C.
It can be molded into any shape in 10 to 30 minutes at a temperature range of °C, has good transferability, and produces molded products with satisfactory physical properties as PRTP. If the polymerization rate is less than 40%, the resulting prepreg has a strong monomer odor and is sticky, so if you mask both sides with polyethylene film and handle it, the masking will peel off, and the molding will foam. Therefore, good molded products cannot be obtained. On the other hand, when the polymerization rate exceeds 60%, the resulting prepreg becomes hard.

During the molding process, peeling may occur between the fiber base material and the resin, and the moldability and transferability of complex shapes may deteriorate.
Mercaptans as chain transfer agents, ultraviolet absorbers, and ultraviolet absorbers, which are commonly used as chain transfer agents within the range that satisfies the conditions of the present invention;
Stabilizers, lubricants, dyes and pigments, etc. may be added.

The present invention will be explained in more detail with reference to Examples below.

Examples 1-12. Comparative Examples 1 to 8 The types and amounts of initiators selected from radical polymerization initiators (A) and (B) were determined based on 100 parts by weight of a mixture of vinyl monomers copolymerizable with methyl methacrylate. The mixture was varied and mixed uniformly. Two tempered glass plates are set between two hot plates in a heating furnace, a glass mat (made by M-11609 and -450 Asahi fiberglass ■) is held between them, and the gap is filled with soft polyvinyl chloride. Maintain 4WK as a gasket, set a thermocouple, inject the above mixture, and after degassing, heat and polymerize at a specified temperature 1
The desired methacrylic resin prepreg was obtained by cooling during the exothermic peak. Next, this prepreg sheet was heat-formed using a press mold at 120° C. and sOkg/caG for 10 minutes to form a tray with 20011 square sides and 50111 mm depth. These polymerization recipe 1 conditions and evaluation results are shown in Table 1, including comparative examples.

The monomers and radical polymerization initiators used in Table 1 are each represented by the following abbreviations.

MMA: Methyl methacrylate MA Methyl diacrylate EA Ethyl diacrylate St: Styrene A-1 diisopropyl peroxydicarbonate A-2 dicyclohexyl peroxyneodecanoate A-3 = tert-butyl peroxyneodecanoate A-4: Isobutyl peroxide A-5: 2,2'-azobis-4-methoxy-2,4-
Dimethylpaleronite IJ Ru A-6: tert-butyl peroxypivalate B-1
: ditertiarybutyl peroxyhexahite 0 lotephthalate B-2: 2,2'-ditertiarybutyl peroxybutane B-3 dichlorohexanone peroxide B-4: tertiarybutyl cumyl peroxide B-5: 2- Carbamol Azobisisobutyronitrile

Claims (4)

[Claims] (1) For 100 parts by weight of a monomer mixture consisting of 60-100% by weight of methyl methacrylate and 40-0% by weight of a copolymerizable vinyl monomer, the 10-hour half-life temperature is 50%.
℃ or below (1 to 0.3 parts by weight of AlO0O and 0.1 to 1.0 parts by weight of a radical polymerization initiator (B) with a 10-hour half-life temperature of 70°C or higher are added to the fiber base material. A method for producing a methacrylic resin prepreg, characterized in that heating polymerization in the presence of K brings the polymerization rate of the system to 40 to 60%. (2) Radical polymerization initiators (A) and (B) 10
Claim 1 in which the time half-life temperature is as follows:
The method for producing prepreg described in Section 1. TB −TA≧30 ・・・・・・・・・(1) TA:
10-hour half-life temperature ('C) of radical polymerization initiator (Al) TB: 10-hour half-life temperature ('C) of radical polymerization initiator (B) (3) Radical polymerization initiator (Al and (Bl)
Claim 1 in which the time half-life temperature is as follows:
The method for producing prepreg described in Section 1. TA <'rp< TB -20・・・・・・・・・
・(2)'rp≦60 ・・・・・・・・・(3)TP
: Polymerization temperature ('C) (4) The fiber base material is glass, mica, or polyamide. The method for producing Gripreg according to claim 1, characterized in that the material is cloth, mat, or nonwoven paper made of polyester or the like.