JP2766509B2 - Methacrylic resin molding material excellent in adhesiveness and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a methacrylic resin molding material having excellent adhesiveness and a method for producing the same. More specifically, the present invention relates to an improved technique for imparting tackiness to a methacrylic resin molding material for obtaining a crosslinked molded product.

[Conventional technology]

Generally, methacrylic resin containing methyl methacrylate as a main component is used in various fields such as lighting covers, automobile parts, signboards, decorative articles, and miscellaneous goods due to its excellent weather resistance and outstanding transparency. Since the methacrylic resin is a linear polymer, there is a defect that heat resistance, solvent resistance, impact resistance, and surface hardness are insufficient.
For example, the limit of heat resistance is about 100 ° C., and at present, it cannot sufficiently meet the demands from various fields that require heat resistance. For example, it cannot be used as a headlamp cover as an automobile part, and in the case of a tail lamp, the size of the lamp itself becomes larger or the illuminance increases, the number of heat generators increases, and the thickness decreases due to cost reduction compared to conventional products It is expected that heat resistance will be improved from both sides, and that it will be used for parts that increase the temperature under direct sunlight, such as meter covers for automobiles and motorcycles (motorcycles) and water heater covers using solar thermal energy. So
The development of a methacrylic resin that can withstand even the boiling point of water or more is expected.

Conventionally, for the purpose of improving the heat resistance of methacrylic resin,
Various methods have been proposed.
Japanese Patent Publication No. 2128 proposes a molding material comprising a specific partially crosslinked gel polymer, which is suitable for molding accompanied by flow by injection molding, extrusion molding, transfer molding or the like, and a method for producing the same.

[Problems to be solved by the invention]

According to the methacrylic resin molding material described in JP-A-60-202128, a crosslinked molded article excellent in physical properties such as heat resistance and solvent resistance can be obtained without lowering transparency. However, as described in the above publication, the methacrylic resin molding material is not sticky and has shape retention, so when kneaded and used for the purpose of increasing fluidity, a high polymer is used. In the case of a partially crosslinked gel polymer obtained by partially polymerizing the containing region or a mixture of monomers alone, the crushed material becomes fine and loose, resulting in inconvenient handling and handling of complicated molded product shapes In the case where the material is preliminarily formed into the shape or the material is supplied in advance, there have been problems such as difficulty in maintaining the shape of the preformed body, complicated material supply, and inconvenience in handling. In addition, even when fillers such as inorganic powders such as aluminum hydroxide, alumina, silica, talc, and calcium carbonate, and fillers such as glass fibers and wood powders are kneaded and contained in the molding material, there is no tackiness, so that uniform mixing is difficult. In particular, when using a crushed product of a partially cross-linked gel polymer obtained by partially polymerizing a mixture of monomers alone, there is a problem that cracking of a molded product due to uneven mixing is likely to occur due to the amount of filler added. there were.

Therefore, in order to solve the above-mentioned problems, the present invention improves the methacrylic resin molding material to impart adhesive strength, and further improves the handleability and facilitates uniform mixing of fillers and the like. An object is to provide a material and a method for manufacturing the same.

[Means for solving the problem]

The present inventors have intensively studied various materials for the problem to be solved, and as a result, crushed the partially crosslinked gel polymer described in JP-A-60-202128 and added a specific amount of syrup The present inventors have found that the addition of methacrylonitrile can impart an appropriate degree of tackiness to the methacrylic resin molding material, thereby completing the present invention.

That is, an object of the present invention is to comprise (A) 40 to 99% by weight of an unsaturated monomer mainly composed of alkyl methacrylate and optionally containing a polymer and (B) 60 to 1% by weight of a crosslinking agent. A partially crosslinked gel-like polymer 100 in which the content of the polymer is increased by 4 to 62% by weight as compared with the polymer content in the mixture within a range where the total polymer content does not exceed 80% by weight. and parts by weight, mainly composed of alkyl methacrylates consists of a syrup 1-100 parts by weight containing dissolve the polymer, the better the methacrylic resin molding material adhesive having an adhesive strength of 30~900g / cm ² Achieved.

Further, the above-mentioned objects are to provide a mixture comprising (A) 40 to 99% by weight of an unsaturated monomer mainly composed of alkyl methacrylate and optionally containing a polymer and (B) 60 to 1% by weight of a crosslinking agent. By partially polymerizing in the presence of a polymerization initiator, the content of the polymer is increased by 4 to 62% by weight from the polymer content in the mixture so long as the total polymer content does not exceed 80% by weight. 100 parts by weight of partially crosslinked gel-like polymer, and 1 to 100 parts by weight of a syrup containing alkyl methacrylate as a main component dissolved and containing the polymer are crushed, mixed, and kneaded substantially uniformly. This is achieved by a method for producing a resin molding material.

 Hereinafter, the present invention will be described in more detail.

In the present invention, mainly alkyl methacrylate,
The unsaturated monomer (A) which may contain the polymer is defined as alkyl methacrylate alone or other α, β-
The syrup is a mixture with an ethylenically unsaturated monomer or a syrup containing these polymers dissolved in the monomer or monomer mixture. Alkyl methacrylates include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert
-Butyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, dicyclopentenyl methacrylate, etc., alone or as a mixture; lower alkyl methacrylates having 1 to 4 carbon atoms are preferred, and methyl methacrylate is particularly preferred.

Examples of copolymerizable monomers include methyl acrylate,
Ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-
Alkyl acrylates such as ethylhexyl acrylate, cyclohexyl acrylate, lauryl acrylate and dicyclopentenyl acrylate; hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate and 3-hydroxybutyl acrylate; 2-hydroxyethyl methacrylate; 2-hydroxy Propyl methacrylate, 4-
Hydroxybutyl methacrylate, 2-hydroxy-3
-Hydroxyalkyl methacrylates such as chloropropyl methacrylate, acrylic acid, methacrylic acid, neodymium acrylate, acrylates such as lead acrylate, neodymium methacrylate, methacrylates such as lead methacrylate, vinyl chloride, vinyl acetate, acrylonitrile, Methacrylonitrile, acrylamide, methacrylamide,
Styrene, α-methylstyrene, vinyltoluene, maleic anhydride and the like can be mentioned.

The syrup containing the alkyl methacrylate or a polymer of a monomer mixture containing alkyl methacrylate as a main component generally has a viscosity of 1 to 10,000 centipoise at 25 ° C., and 3 to 40% by weight, preferably A monomer solution containing 6 to 30% by weight of a polymer.

The crosslinking agent (B) used in the present invention has at least two (meth) acryloyl groups in the molecule, and has a crosslinkable monomer having 10 or less carbon atoms between the (meth) acryloyl groups. It is preferable that the compound is in the form of, for example, the following formulas (1) to (3): MA—O— (CH ₂ ) _n —O—MA (1) wherein n is an integer of 3 to 6, and MA is Represents a methacryloyl group. ] (Where R ₁ is a group of H, CH ₃ , C ₂ H ₅ , CH ₂ OH R ₃ represents a group of H or CH ₃ , R ₁ , R ₂ and R ₃ are not simultaneously hydrogen, and (M) A represents a methacryloyl group or an acryloyl group. ] _{(M) AOCH 2 CH 2 O} n (M) A ...... (3) [where n is 1 or 2, (M) A represents a methacryloyl group or an acryloyl group. ] It is an unsaturated monomer represented by these. Specifically, 1,3-
Propylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexanediol methacrylate, 1,3-butylene glycol dimethacrylate, dimethylolethanedimethacrylate, 1,1
-Dimethylolpropane dimethacrylate, 2,2-dimethylolpropane dimethacrylate, trimethylolethanetri (meth) acrylate, trimethylolpropanetri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolmethanedimethacrylate, Examples thereof include ethylene glycol di (meth) acrylate and diethylene glycol di (meth) acrylate. Among these crosslinkable monomers, those represented by the above formula (2) are preferably used, and they have a high transparency and a high fluidity. In particular, 2,2-dimethylolpropane dimethacrylate (neopentyl glycol dimethacrylate) is desirable.

The amount of the crosslinking agent (B) to be used is 1 to 60% by weight, preferably 2 to 50% by weight, more preferably 4 to 30% by weight. If the amount used is less than 1% by weight, the solvent resistance and heat resistance of the finally obtained molded article cannot be sufficiently improved, while if it exceeds 60% by weight, the finally obtained molded article becomes brittle. In addition, the fluidity of the molding material tends to deteriorate, which is not preferable.

The partially crosslinked gel-like polymer of the methacrylic resin molding material according to the present invention comprises (A) an alkyl methacrylate as a main component, an unsaturated monomer which may contain and dissolve the polymer, and (B) a crosslinking agent. The mixture obtained by heating the mixture in the presence of a polymerization initiator is polymerized, and the reaction is stopped when a part of the monomer present in the mixture has reacted without reacting the entire amount of the monomer present in the mixture. Is a partially crosslinked polymer.

In this case, the content of the polymer present in the partially crosslinked gel-like polymer is determined by the unsaturated monomer (A) and the crosslinking agent (B).
4 to 62% by weight, preferably 10 to 62% by weight, most preferably 15 to 62% by weight higher than the polymer content in the mixture, and a total polymer content of 80% by weight, preferably 62
% By weight. When the value of the polymer content is less than 4% by weight, the product does not show a gel state,
If the handling is inconvenient, while the value increased by 62% by weight or more or the upper limit of 80% is not preferable because good flow does not occur during molding.

When preparing the partially cross-linked gel polymer in the present invention, usually using a polymerization initiator, it is possible to use one or a mixture of two or more selected from ordinary low-temperature active polymerization initiator and high-temperature active polymerization initiator it can. In general, a low-temperature active polymerization initiator is suitable for the preparation of a partially crosslinked gel polymer, and the decomposition temperature for obtaining a half-life of 10 hours is 50 ° C. or lower, preferably 26 to 45 ° C., particularly 26 to 41 ° C. Radical polymerization initiators of oxides and azo compounds are preferably used. The amount of the unsaturated monomer (A) and the crosslinking agent (B)
0.002 to 1% by weight, preferably 0.002% by weight based on the total amount of
~ 0.1% by weight.

The high-temperature active polymerization initiator is particularly suitable for polymerization under molding conditions in the present invention, and a polymerization initiator having a decomposition temperature of 60 to 220 ° C. is preferable, for improving the molding cycle and storage stability.
Polymerization initiators having a decomposition temperature of 70-170 ° C are more preferred. The amount used is 0.02 to 5% by weight, preferably the total amount of the unsaturated monomer (A) and the crosslinking agent (B).
0.05 to 4% by weight.

In the present invention, the partially crosslinked gel polymer is produced by heating a mixture of the unsaturated monomer (A) and the crosslinking agent (B) in the presence of a polymerization initiator. This polymerization reaction is 10 ~
It is carried out at a temperature of 100 ° C., preferably 35-90 ° C., for 10-200 minutes, preferably 20-150 minutes. Here, when both the low-temperature active polymerization initiator and the high-temperature active polymerization initiator are used together, almost all of the low-temperature active polymerization initiator is consumed, but the high-temperature active polymerization initiator remains as it is without being decomposed up to the reaction temperature. And
Acts as a polymerization initiator in subsequent molding processing conditions.

These high temperature active polymerization initiators may be added together with the low temperature active polymerization initiator at the time of preparing the partially crosslinked gel polymer, or may be added when kneading and kneading with a kneader or an extruder after preparing the partially crosslinked gel polymer. A high temperature active polymerization initiator may be added to a syrup to be added for the purpose of modifying the fluidity and tackiness of the partially crosslinked gel polymer, and then crushed and mixed together with the partially crosslinked gel polymer. May be kneaded uniformly.

A partially crosslinked gel polymer having a desired polymerization rate can be obtained by stopping the polymerization reaction by quenching or the like,
Further, when a mixture of the unsaturated monomer (A) and the crosslinking agent (B) is heated and polymerized in the presence of the polymerization initiator,
It can be easily obtained by adding the following regulators. Such regulators include 1,4 (8) -P-menthadiene, 2,6-dimethyl-2,4,6-octatriene, 1,4
-P-menthadiene, 1,4-cyclohexadiene, and α-methylstyrene dimer.

Such a modifier is present in an amount of 0.0001 to 0.5% by weight, preferably 0.001 to 0.2% by weight, and most preferably 0.005 to 0.1% by weight, based on the total amount of the unsaturated monomer (A) and the crosslinking agent (B). Used in the range.

The raw material mixture before polymerization of the partially crosslinked gel polymer of the present invention may contain additives such as a chain transfer agent, a coloring agent, and a filler, if necessary.

Since the partially crosslinked gel-like polymer of the present invention is not sticky as it is and has shape retention properties, it can be easily handled in any shape such as sheets, rods, blocks, pellets, etc. It flows by applying a shear stress at a temperature. Further, it can be crushed for the purpose of improving fluidity. Those with an average particle size of 5 mm or less,
Preferably, by crushing to a size of 2 mm or less, extremely stable fluidity can be obtained, and when the total polymer content is relatively low, for example, not exceeding 50% by weight, screws, calendar rolls, etc. Performed using a kneader, if the total polymer content is relatively high, ball mill,
The crushing can be easily performed by using a crusher such as a cutter mill.

The methacrylic resin molding material having excellent adhesiveness according to the present invention is mainly composed of the (A) alkyl methacrylate,
A mixture of an unsaturated monomer which may contain and dissolve the polymer and (B) a crosslinking agent is partially polymerized in the presence of a polymerization initiator, and the total amount of the monomer in the mixture is reacted. 100 parts by weight of the partially crosslinked gel-like polymer obtained by stopping the reaction at the stage where a part of the polymer has been reacted, and a syrup 1 containing alkyl methacrylate as a main component and containing the polymer dissolved therein Consisting of ~ 100 parts by weight, 3
It has an adhesive strength of 0 to 900 g / cm ² .

The highly adhesive methacrylic resin molding material of the present invention is based on 100 parts by weight of the partially crosslinked gel polymer or its crushed partially crosslinked gel polymer, and contains the polymer mainly containing alkyl methacrylate in a dissolved manner. The syrup can be prepared by adding 1 to 100 parts by weight, preferably 10 to 50% by weight, and kneading substantially uniformly, whereby the following advantageous effects can be imparted.

(I) Since the fluidity can be further improved, the fluidity can be adjusted by the addition amount of the syrup.

(Ii) it can impart tackiness and its degree can be adjusted.

(Iii) Preforming is easy, and handling of the preformed body is easy.

(Iv) The effect of kneading the filler can be improved.

(V) In the case of coloring a molded article, a dye or pigment is mixed with a syrup, and the syrup is added to and mixed with the crushed partially crosslinked gel polymer so as to be uniformly colored, thereby suppressing generation of a flow pattern and an uneven spot pattern. It becomes easier.

If the added amount of the syrup exceeds 100 parts by weight, the shape retention of the composition cannot be maintained, which is not preferable.

The syrup that may be contained by dissolving the polymer based on the alkyl methacrylate means a syrup containing the polymer of the monomer mixture containing the alkyl methacrylate or the alkyl methacrylate as a main component, preferably 25 ° C. And has a viscosity of 4 to 50 poise, more preferably 6 to 20 poise, and can contain 50% by weight or less of a crosslinkable monomer as needed. It is desirable to contain the same concentration of a crosslinkable monomer. As a method of adding and substantially uniformly kneading the syrup, the kneading machine or the crusher can be used when the partially crosslinked gel-like polymer is not crushed. Can be performed using a mixing stirrer such as a super mixer or a Henschel mixer.

Here, "substantially uniformly kneading" means that the syrup kneaded in the molding material is kneaded to such an extent that the syrup kneaded in the molding material is separated by leaving it at room temperature for a short time and does not flow out. This state can be achieved by stirring and mixing for several minutes to about 10 minutes.

The adhesive strength of the present invention is measured by the following apparatus and method, and the molding material of the present invention has an adhesive strength of 30 to 900 g / cm ² , preferably 50 to 700 g / cm ² . If the adhesive strength is less than 30 g / cm ² , the adhesive strength is weak, so it is difficult to maintain the shape of the preformed body, while if it exceeds 900 g / cm ² , it is difficult to adhere to packaging materials, container walls, etc. , Work becomes very difficult. The adhesive strength was measured using a tackiness analyzer (Marubishi Kagaku Seisakusho Seisakusho; precision strength gauge PG-10).
-20 (manufactured by Kyowa Gas Chemical Industry Co., Ltd.) and nylon, place a measurement sample, apply a load of 10 kg, and apply an adhesive area of 40 × 40
(Mm), which can be determined by measuring under conditions adjusted so that the thickness of the adhesive layer is 0.3 mm.

The methacrylic resin molding material according to the present invention has a compression molding method, an extrusion molding method, a transfer molding method of 90 to 180 ° C.,
The molded article having a desired shape can be obtained by heating at a temperature of preferably 90 to 150 ° C. for 1 to 30 minutes, preferably 2 to 5 minutes.

Hereinafter, the present invention will be described in detail based on examples.

Example 1 A polymerization initiator and a polymerization regulator shown in Table 1 were mixed and dissolved in a mixture of a resin raw material shown in Table 1 and a crosslinking agent, and the mixture was assembled so as to have a distance of 10 mm between two glass plates. The mixture was poured into a cell and polymerized at 60 ° C. for 2.5 hours to obtain a gel-like partial polymer. The polymer content of the gel-like partial polymer was as shown in Table 1. This polymer is screw diameter 50mm, L /
When extruded with an extruder of D = 8, a molding material composition crushed to a maximum particle size of 2 mm or less was obtained. This composition contains the same concentration of a crosslinking agent as contained, and has a viscosity average degree of polymerization of 10.0.
And a polymethacrylate syrup having a viscosity of 8 poise and containing polymethyl methacrylate of No. 00 in a ratio shown in Table 1.
As shown in the table, adhesive properties were obtained, and a molding material composition having improved fluidity was obtained. Next, 300 g of this composition is made into a dango and
Put into a mold heated to 130 ° C. and having a size of 200 mm in length and 250 mm in width, hold at the initial pressure shown in Table 1 for 2 minutes, raise the pressure to 200 kg / cm ² and hold for 20 minutes, The mold was opened and removed. The gel polymer flows, and the molded product with good appearance like a mold (length 200mm, width 250mm, thickness 5m)
m) was obtained, and burr generation was hardly observed.

Examples 2 to 10 Using the same apparatus and conditions as in Example 1, a partially crosslinked gel polymer was obtained with various compounding compositions, and compressed under the same conditions as in Example 1 except that the initial pressure was shown in Table 1. The molding was performed to obtain a molded article having a good appearance.

Examples 11-20 240 g of the molding material composition used in Examples 1-10
A band-shaped preform obtained by compressing in a mold at room temperature so as to be 0 mm, width 45 mm, thickness 7 mm is 800 mm long, 50 mm wide, 3 depth
Molding was carried out under the same conditions as in Example 1 except that it was charged into a 0 mm strip-shaped mold. The results are as shown in Table 2. The molding material composition flowed to fill the entire space of the mold, and a molded article having a good appearance as in the mold was obtained.

Comparative Examples 1 to 3 An attempt was made to preform the molding material composition into a strip in the same manner as in Example 11 except that the molding material composition shown in Example 11 was changed to the molding material composition shown in Table 3. However, it could not be formed into a strip because it was uneven. For this reason, it was attempted to put the molding material composition into the mold as it was, but it was difficult to put a predetermined amount of the molding material composition as a part of the molding material composition overflowed.

Comparative Example 4 40 parts by weight of the crushed molding material composition obtained in Example 1 and aluminum hydroxide (BW-103, manufactured by Nippon Light Metal Co., Ltd.) 60
Compression molding was carried out under the same conditions as in Example 1 except that the mixture was kneaded and mixed with the parts by weight. However, the molding material composition did not flow, not only did not completely fill the mold space, but also the obtained molding was performed. Cracks occurred in the entire product, and a good molded product could not be obtained.

〔The invention's effect〕

As described above, the present invention comprises (A) 40 to 99% by weight of an unsaturated monomer mainly composed of alkyl methacrylate and optionally containing a polymer and (B) 60 to 1% by weight of a crosslinking agent. Crushed product of a partially crosslinked gel polymer in which the content of the polymer is increased by 4 to 62% by weight as compared with the polymer content in the mixture as long as the total polymer content does not exceed 80% by weight. 100 parts by weight, mainly composed of alkyl methacrylates consists of a syrup 1-100 parts by weight containing dissolve the polymer, because it is methacrylic resin molding material having an adhesive force of 30~900g / cm ^2, syrup Medium stickiness,
Since the composition has fluidity, the use of this composition is useful for obtaining a molded article having good heat resistance and solvent resistance and excellent transparency, and the composition has good fluidity. In addition, the shape is easy to handle, and the shape of the molded product can be freely adjusted. This is particularly suitable for obtaining a molded product having a complicated shape.

The present invention also relates to an unsaturated monomer (A) mainly composed of alkyl methacrylate and optionally containing a polymer dissolved therein.
A mixture comprising 40 to 99% by weight and (B) 60 to 1% by weight of a cross-linking agent is used so that the content of the polymer is lower than the content of the polymer in the mixture as long as the total polymer content does not exceed 80% by weight. 4-62
100 parts by weight of the crushed partially cross-linked gel polymer whose weight% has been increased, and 1 to 100 parts by weight of a syrup mainly containing alkyl methacrylate and containing the polymer dissolved therein are crushed and mixed to be substantially uniformly kneaded. Since it is a method for producing a methacrylic resin molding material, a molding material composition having tackiness and fluidity comparable to syrup and easy to handle can be provided easily and usefully.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C08L 33/10 C08L 33/10 (56) References JP-A-63-30511 (JP, A) JP-A-62-20513 (JP) JP-A-60-202128 (JP, A) JP-A-2-157146 (JP, A) JP-A-2-294376 (JP, A) JP-A-2-202504 (JP, A) (58) Surveyed field (Int.Cl. ⁶ , DB name) C08F 20/00 C08F 220/00 C08F 2/00 C08L 33/00 C08J 5/00

Claims (5)

(57) [Claims] (1) an unsaturated monomer (A) comprising alkyl methacrylate as a main component and optionally containing a polymer dissolved therein;
A mixture consisting of 99% by weight and (B) a crosslinking agent of 60 to 1% by weight has a polymer content of 4 to 4% higher than the polymer content in the mixture as long as the total polymer content does not exceed 80% by weight. 30 parts by weight of 100 parts by weight of a partially-crosslinked gel polymer crushed by 62% by weight and 1 to 100 parts by weight of a syrup mainly containing alkyl methacrylate and containing the polymer dissolved therein,
A highly adhesive methacrylic resin molding material having an adhesive strength of up to 900 g / cm ² . 2. The molding material according to claim 1, wherein the alkyl group of the alkyl methacrylate has 1 to 4 carbon atoms. 3. The molding material according to claim 2, wherein the alkyl methacrylate is methyl methacrylate. 4. The crosslinking agent according to claim 1, wherein the crosslinking agent has at least two (meth) acryloyl groups in the molecule and the number of carbon atoms between the (meth) acryloyl groups is 10 or less. 4. The molding material according to any one of 1 to 3. 5. An unsaturated monomer (A) comprising (A) an alkyl methacrylate as a main component and optionally containing a polymer of the same.
A mixture consisting of 99% by weight and (B) a crosslinking agent of 60 to 1% by weight is partially polymerized in the presence of a polymerization initiator, so that the total polymer content does not exceed 80% by weight. 100 parts by weight of a partially crosslinked gel-like polymer in which the polymer content of the mixture is increased by 4 to 62% by weight, and 1 to 100 parts by weight of a syrup mainly containing alkyl methacrylate and containing the polymer dissolved therein. A method for producing a methacrylic resin molding material having excellent tackiness, comprising crushing, mixing and kneading substantially uniformly.