JPS6016445B2 - Method for producing glass fiber concentrate for thermoplastic resin reinforcement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing glass fiber concentrates suitable for obtaining thermoplastic resin compositions reinforced with glass fibers, and more particularly to a method for producing glass fiber concentrates suitable for obtaining thermoplastic resin compositions reinforced with glass fibers. The present invention relates to a method for producing glass fiber concentrates which are suitable for producing glass fiber reinforced thermoplastic molding materials having impact resistance, heat resistance and appearance.

It is known that thermoplastic resins can be filled with glass fibers to modify their properties and enhance certain properties.

However, thermoplastic resins containing glass fibers undergo discoloration during melt molding, and some types of thermoplastic resins experience a decrease in molecular weight during this process. There are cases where it becomes negative or cancels out, making it impossible to fully achieve the objective. In the case of glass fibers, chromium compounds, silane compounds, boron compounds, etc. that are treated and adhered to the glass fibers can cause discoloration and polymer collapse during molding, and inorganic substances that have not been treated with sizing agents In this case, the acidic active sites, strong chlorine activity, etc. are the cause, and at the same time, it is impossible to produce chopped strands without a sizing agent, and when filling the thermoplastic resin, it is necessary to fill the resin with sufficient filling. It is often ineffective.

In order to prevent such defects and achieve better filling effects, for example, Japanese Patent Publication No. 47-122447 and Japanese Patent Publication No. 47-122447,
As described in Japanese Patent Application No. 8-41261, a glass fiber concentrate is prepared by coating a filler material such as glass fiber with a thermoplastic resin in advance, and the heat is applied to strengthen the concentrate. A method of blending it into a plastic resin is known. When using such methods, it is important how the glass fiber concentrate is produced. Currently, three methods are known for producing glass fiber concentrates: '1' Method of coating glass fiber with an organic solvent solution of thermoplastic resin ■ Method of coating with emulsion of thermoplastic resin '3'
Method of Coating by Polymerization on the Coating Material Among the above methods, method 0-- requires the organic solvent to be dispersed, which has the disadvantage of deteriorating the working environment.

In addition, when using method (2), there is no problem of worsening the working environment as with method (m), but when the glass fiber is in the form of a strand, it is not possible to fill the resin to the inside of the strand. However, there is a problem that glass fiber cannot be coated firmly. The method {31] is a method in which glass fibers are soaked in a monomer containing a catalyst and subjected to polymerization, and is preferable because it does not have the drawbacks of the above methods '1} and (2). As a method for this lake, the method described in Japanese Patent Publication No. 49-27663 is known. However, concentrates obtained by this method have been found to have problems when used at high temperatures. That is, when a thermoplastic resin material containing this type of concentrate is used in applications where it is used at high temperatures, there is a problem in that the mechanical strength at high temperatures is poor. This type of concentrate is often incorporated into various engineering plastics, so
It is undesirable that the mechanical strength is poor at high temperatures. In view of this situation, the present inventors have conducted intensive studies to provide a concentrate for glass fiber-reinforced thermoplastic compositions that can be blended into various engineering plastics and have excellent mechanical strength at high temperatures. An acrylic silane compound is further mixed into a mixture of an aromatic compound monomer or a vinyl aromatic compound monomer and another monomer that can be copolymerized therewith, and the mixture is aqueous suspended in the presence of chopped glass fiber strands. Upon polymerization, the chopped glass fiber strands are arranged in a uniform direction and are coated with a polymer to obtain a glass fiber concentrate similar in shape to a pellet produced using an extruder. It was discovered that a thermoplastic molding material blended with a fiber concentrate has excellent mechanical strength at high temperatures, and the present invention was achieved based on this discovery.
An object of the present invention is to provide an industrially advantageous method for producing a glass fiber concentrate that can be blended into various engineering plastic materials and yields a molding material with excellent mechanical strength at high temperatures.

However, the purpose of this lever is to obtain 5 to 50% of chopped glass fiber strands per 100 parts by weight of a single field composite of a vinyl aromatic monomer or a vinyl aromatic monomer and other monomers that can be co-polymerized with the vinyl aromatic monomer. 800 parts by weight, 100-3 including suspension stabilizer
0.00 parts by weight of the aqueous medium and 0.01 to 2.0 parts by weight of the glass fiber chopped strands. This can be easily achieved by carrying out the polymerization in the presence of an acrylic silane compound in an amount of . Hereinafter, the method of the present invention will be explained in detail. The vinyl aromatic monomer used in the present invention is most typically styrene, but in addition, vinyltoluene,
Examples include pinylethylbenzene and Q-methylstyrene. These may be used alone or in combination of two or more. Further, other monomers that can be copolymerized with the vinyl aromatic compound referred to in the present invention include acrylic. Vinyl cyanide compounds such as nitrile and methacrylonitrile, acrylic acid,
Methyl acrylate, ethyl acrylate, methacrylic acid,
Examples include unsaturated carboxylic acids such as methyl methacrylate and ethyl methacrylate, and their esters. The monomer to be copolymerized with the vinyl aromatic compound may be used alone or in combination of two or more. As a combination of monomers, a combination of a monovinyl aromatic compound and a vinyl cyanide compound is particularly preferred.

In the method of the present invention, examples of the acrylic silane compound include y-methacryloxypropylethoxysilane, y-methacryloxypropylmethyldiethoxysilane, y-methacryloxypropyl-tris-(2-methoxyshethoxy)silane, etc. It will be done.

In the method of the present invention, the amount of these acrylic silane compounds used is 0.01 to 2.0% based on the chopped glass fiber strands present in the polymerization system. % by weight.

If the amount of the acrylic silane compound used is less than the above range, it is undesirable. Even if a glass fiber concentrate is added, the mechanical strength of the compound at high temperatures will not improve, so it is not preferable to use more than the above range. Not only will the effect of this change be less noticeable, but it is also unfavorable from an economic standpoint. The chopped glass fiber strand as referred to in the present invention is a strand in which hundreds to thousands of pieces having a diameter of 20 French or less are bundled, and has a length of 1 to 15 ribs.

If the length of the strand is less than one side, the glass fiber exhibits properties only as a filler, and the mechanical properties of the final molded product cannot be improved, which is not preferable. On the other hand, if the length is 15 ribs or more, the resulting resin composition containing the glass fiber concentrate is undesirably long and difficult to mold.
In the method of the present invention, the monomer, an acrylic silane compound, and a chopped glass fiber strand are present in the polymerization system, and polymerization is carried out by a suspension polymerization method. The amount of chopped glass fiber strands present in the polymerization system during polymerization can be from 5 to 80 parts by weight per 10 parts by weight of monomer, especially when the ratio of monomer to glass fiber is 10 parts by weight. $
A range of 20 to 400 is suitable. In the process of the invention, the proportion of the aqueous medium containing the suspension stabilizer is 10
The amount is 100 to 300 parts by weight.

If the amount of the aqueous medium per part by weight of monomer 10 is less than the above range, as the polymerization reaction progresses, the entire product mixture becomes extremely semi-occupied, making it difficult to inspect the product mixture, and also causing heat resistance. This is undesirable because it causes disadvantages such as poor transmission and therefore difficulty in temperature control, making it impossible to obtain a concentrate with uniform properties. If the amount of the aqueous medium is 300 parts by weight or more, the amounts of the charged monomer and the chopped glass fiber strands will inevitably decrease, which will reduce productivity and be uneconomical, which is undesirable. The polymerization reaction is carried out by the suspension method as described above, and the suspension stabilizers that can be used at this time are those that are normally used when carrying out suspension polymerization.
Examples include water-soluble polymer compounds such as various saponified products of polyvinyl acetate (polyvinyl alcohol), styrene-maleic acid copolymers, polysodium methacrylate, and copolymers of ethylhexyl acrylate and acrylic acid. They can be used alone or in combination of two or more.

Further, these suspending agents and a certain kind of surfactant can be used in combination, or a certain kind of surfactant and an inorganic suspending agent can also be used in combination. The suspension polymerization reaction according to the method of the present invention can be carried out using a conventional suspension polymerization reactor, and can be carried out by rotating a cylindrical reactor in the circumferential direction of the tube, or by rotating the reactor in an inverted type. This can also be accomplished by rotating the

Surprisingly, in the product obtained by the method of the present invention, the surface of each chopped glass fiber strand is coated with a polymer, and a large number of these glass fibers are arranged and assembled in a certain direction, giving the product an appearance similar to that produced by an extruder. This results in a glass fiber concentrate similar in form to pellets.

These can be used as they are by dry blending them with thermoplastic resin pellets or granules to be blended. The thermoplastic resin that can be blended may be a resin that is compatible with the base resin of the glass fiber concentrate obtained by the method of the present invention, or a resin that is not compatible with the base resin. Such resins include glass fiber-free polyethylene, polypropylene, polycarbonate, polyamide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyacetal,
Examples include polysulfone, A-spotted resin, AS resin, polystyrene, polyvinyl chloride, and copolymers mainly composed of vinyl chloride. The ratio of resins to be blended can be changed as appropriate depending on the intended use of the reinforcing material. As above,
The glass fiber concentrate obtained by the method of the invention has extremely high utility value since it can be dry blended with other thermoplastic resins and subjected to molding.

In addition, in the glass fiber concentrate obtained by the method of the present invention, not only the surface of the glass fiber is coated with the polymer, but also the inside of the single fibers constituting the chopped strand is filled with the polymer. Therefore, the glass fibers are less likely to break during molding, there is less friction between the molding machine and the glass fibers, and there is less damage to the molding machine. In addition, in the glass fiber concentrate obtained by the method of the present invention, the chopped glass fiber strands are coated with a polymer containing an acrylic silane compound, so this can be used by dry blending it with other thermoplastic resins. In this case, the resulting molding material has excellent mechanical strength at high temperatures, so its industrial utility value is extremely high. Hereinafter, the method of the present invention will be explained in detail according to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 The following proportions were charged into a three-glass autoclave equipped with a hawk-equipped calendar, a reflux condenser, a nitrogen gas inlet, a thermometer, etc.

Glass fiber chopped strand (length 3 side) 315.
0 Styrene 81.0 Acrylonitrile 54.0
Tymethacryloxypropyltrimethoxysilane 0.
Group 5 Suspending agent (copolymer of ethylhexyl acrylate and acrylic acid) 0. pine 5ta penzoyl peroxide 1.01ta water
The contents charged in the 1,800° autoclave were heated to 80°C under a nitrogen stream while being stirred, and the reaction was continued at this temperature for 5 hours.

Thereafter, the internal temperature of the autoclave was raised to 90 oo, and stripping was performed at this temperature to remove unreacted monomers.
The conversion rate of monomer to polymer was about 94%. A glass fiber concentrate in which glass fibers were coated with a polymer was obtained after 405 minutes, and a polymer powder was obtained in spots. The glass fiber content in the glass fiber concentrate is 77. It was turtle weight %. For glass fiber concentrates, the chopped strands used are 50-5
It was a bundle of 00 strands, and its length was almost the same as that of the chopped glass fiber strands used, with both ends aligned, and it had a bullet-like appearance with a diameter of 2 to 3 willows. Only the glass fiber concentrate was taken out from the obtained product and added to it by SAN-C (manufactured by Mitsubishi Monsanto Chemicals, A
S resin (trade name) pellets were dry blended, the amount of glass fiber in the blend was 2% by weight, test pieces were prepared from the dry blend by injection molding, and various physical properties were measured.

At this time, for the bending test, the ambient temperature during the test was 23:00,
The test was carried out under the following conditions: 50 pm, 70°C and 90°C. The results are shown in Table 1. Example 2 In the method described in Example 1, 0.6 y-methacryloxypropyltrimethoxysilane was used instead of y-methacryloxypropyltris(2-methoxyethoxy)silane.
Polymerization was carried out in exactly the same manner as described in the same example, except that 30% of the polymer was used.The glass fiber concentrate was 400% of glass fiber and had a glass fiber content of 78.1%.

The appearance of this glass fiber concentrate was similar to that obtained by the method described in Example 1. To this concentrate, SAM day (Mitsubishi Monsanto Kasei AS resin, trade name) beret was dry blended in the same manner as described in Example 1,
Test pieces were prepared from the dry blend by injection molding, and various physical properties were evaluated in the same manner as described in Example 1.

The results are shown in Table 1. Comparative Example 1 In the method described in Example 1, except that acryloxypropylmethyljethoxysilane was not used,
Polymerization was carried out in exactly the same manner as described in the same example.

The glass fiber concentrate was dry blended with SAN-C, and various physical properties of this blend composition were evaluated in the same manner as in Example 1. The results are shown in Table 1. Comparative example
2 In the glass fiber concentrate obtained by the method described in Comparative Example 1,
SAN-day was dry blended, and various physical properties of the blended composition were evaluated in the same manner as in Example 1.

The results are shown in Table 1. Table 1 Note Husband IJIS K687
Compliant with 1.

Claims (1)

[Claims] 1 5 to 800 chopped glass fiber strands per 100 parts by weight of a vinyl aromatic monomer or a monomer mixture of a vinyl aromatic monomer and another monomer copolymerizable therewith.
0 parts by weight, based on 100 to 3000 parts by weight of aqueous medium containing suspension stabilizers and chopped glass fiber strands.
．． A method for producing a glass fiber concentrate for reinforcing a thermoplastic resin, characterized in that polymerization is carried out in the presence of 01 to 2.0% by weight of an acrylic silane compound.