JPS6257659B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a glass fiber reinforced thermoplastic resin composition,
More specifically, the present invention relates to a glass fiber-reinforced thermoplastic resin composition that has high heat resistance, high rigidity, and excellent moldability. Acrylonitrile-styrene copolymer (hereinafter referred to as
Glass fiber reinforced resin (abbreviated as AS resin)
-GF resin) has particularly high rigidity and good chemical resistance among many glass fiber reinforced thermoplastic resins, has good mold dimensional reproducibility during molding, and has a low mold shrinkage rate. It has many characteristics, such as being small and having good molding dimensional stability such as less warping of the molded product, and excellent moldability such as being easy to mold with a wide range of molding conditions. It is widely used in automobile instrument panels, cooler line flow fans, propeller fans, etc. However, this AS-GF resin is not necessarily satisfactory in terms of heat resistance, and it is necessary to develop a glass fiber reinforced thermoplastic resin that has even higher heat resistance without impairing the characteristics of the resin. In order to improve the reliability of each part in
Furthermore, it is strongly desired because it can be used not only for coolers, but also as a line/flow fan resin for air conditioners that serve both heating and cooling purposes. The present inventors have conducted various studies in order to meet such demands. For example, styrene
Glass fiber reinforced resin of maleic anhydride copolymer (hereinafter referred to as SMA-GF resin), glass fiber reinforced resin of styrene-methacrylic acid copolymer (hereinafter referred to as SMA-GF resin)
SMAA-GF resin), styrene-acrylic acid copolymer glass fiber reinforced resin (SAA-GF resin)
(abbreviated as “resin”)). However, although these resins can improve heat resistance by 10 to 20°C over AS-GF resins, they have the disadvantage that they are inferior to AS-GF resins in terms of toughness and oil resistance. The present inventors further conducted intensive research to develop a highly practical glass fiber-reinforced thermoplastic resin composition that overcomes these drawbacks, and as a result, the present inventors discovered a copolymer containing a specific six-membered cyclic acid anhydride unit. It has been discovered that a thermoplastic resin composition containing a predetermined ratio of agglomerates and glass fibers has desired properties, and based on this finding, the present invention has been accomplished. That is, the present invention provides (A) (a) general formula (R ₁ and R ₂ in the formula are hydrogen atoms or methyl groups) 5 to 85% by weight of six-membered cyclic acid anhydride units, (b)
1 to 80% by weight of methyl methacrylate units, (c) 1 to 65% by weight of aromatic vinyl compound units, and (d) as desired.
100 parts by weight of a copolymer containing 10% by weight or less of methacrylic acid or acrylic acid units and having a weight ratio of (a) units/(d) units of 3 or more, and (B) 5 to 100 parts by weight of glass fiber. The present invention provides a glass fiber-reinforced thermoplastic resin composition comprising: The resin composition of the present invention requires the use of a copolymer having the above-mentioned specific monomer units. The six-membered cyclic acid anhydride unit (a) in this copolymer improves the heat resistance and toughness of the copolymer, and plays a role in improving the resistance of glass fiber reinforced resin molded articles to thermal cycles. In other words, there is generally a difference in linear expansion coefficient between resin and glass fiber, so brittle materials such as SMAA
SMAA− made of resin or SAA resin reinforced with glass fiber
GF resin, SAA-GF resin, and GPPS-GF resin (polystyrene glass fiber reinforced resin) undergo countless cracks when subjected to a cooling cycle of -30℃ x 1 hour at 60℃ x 1 hour five times, but this Such cracks do not occur in the resin composition of the invention. The unit (a) also serves to eliminate thermal instability based on the units (b) and (d). In other words, when a copolymer containing no (a) unit but consisting of (b) units, (c) units, and (d) units contains glass fiber, a lot of foaming occurs and a large number of particles are formed in the molded product. Due to the formation of air bubbles, the practical strength and heat resistance of the molded article are significantly reduced, making it impossible to obtain the molded article aimed at by the present invention. This (a) unit must be contained in the copolymer in an amount of 5 to 85% by weight, preferably 10 to 60% by weight. Furthermore, the six-membered cyclic acid anhydride unit is produced by intramolecular condensation between (b) units and (d) units or between (d) units, but if this intramolecular condensation is incomplete, the When a polymer is compounded with glass fiber and molded, a large amount of large air bubbles are generated and trapped in the molded product. The reason for this is not necessarily clear, but it may be because the glass fibers act as a nucleating agent for bubble generation, or the glass fibers promote the above-mentioned intramolecular condensation, and methanol is removed by demethanol and dehydration through this intramolecular condensation. It is thought that bubbles are generated due to volatilization. In order to prevent the generation of such bubbles, the weight ratio of (a) six-membered cyclic acid anhydride units to (d) methacrylic acid or acrylic acid units is 3 or more, preferably 10
The number needs to be 15 or more, more preferably 15 or more. The larger this value is, the more difficult it is for bubbles to occur even if the molding temperature becomes high or even if the shape of the molded product becomes more complex or larger. In the present invention, when the content of six-membered cyclic acid anhydride units in the copolymer is less than 5% by weight, when the resin composition of the present invention is molded, the molded product has sufficient heat resistance and thermal stability. cannot be granted, and
If it exceeds 85% by weight, it is not practical because moldability is significantly reduced. Next, the (b) methyl methacrylate unit is for improving oil resistance and mechanical strength, and must be contained in the copolymer in an amount of 1 to 80% by weight. If this amount is less than 1% by weight,
Impact resistance and other mechanical strengths become insufficient, and if it exceeds 80% by weight, heat resistance decreases, which is not preferable. Furthermore, the aromatic vinyl compound unit (c) is
It is used to improve the fluidity of the copolymer and improve the dimensional stability and moldability of the copolymer, such as styrene, α-methylstyrene, nuclear alkyl or halogen-substituted styrene. Units are listed. These aromatic vinyl compound units must be contained in the copolymer in an amount of 1 to 65% by weight. This amount is 1% by weight
If it is less than 65% by weight, the moldability will not be improved, and if it exceeds 65% by weight, mechanical strength and oil resistance will decrease. On the other hand, the (d) unit methacrylic acid or acrylic acid unit is derived from a monomer for forming a six-membered cyclic acid anhydride unit, and both play a role in improving the heat resistance of the copolymer. However, it does not necessarily have to be present. If the content of this (d) unit increases, the thermal stability will decrease and gel-like substances will be more likely to be formed, so the content should be controlled in the copolymer.
It is necessary to suppress the content to 10% by weight or less. Such a copolymer can be prepared by dissolving an aromatic vinyl compound, methyl methacrylate, and methacrylic acid or acrylic acid in a suitable solvent such as methyl ethyl ketone, and adding 1,1-bis(tert-butyl) as a polymerization initiator. Peroxy)-3,3,5-trimethylcyclohexane is added and polymerized at a temperature of about 125°C to a reaction rate of about 50%, and then this reaction mixture is polymerized at a temperature of 260°C under a reduced pressure of 1 to 10 mmHg for 5 to 60%. The solvent and unreacted monomers are removed by holding for a minute, and cyclization is caused by intramolecular condensation of methacrylic acid or acrylic acid and these acids and methyl methacrylate. Produced by forming cyclic acid anhydride units. At this time, by appropriately controlling conditions such as reaction temperature, catalyst amount, and reaction rate, the resulting copolymer can be made to have a viscosity of 3 to 20 centipoise at a temperature of 25°C at a concentration of 10% by weight in methyl ethyl ketone. It is desirable to adjust as follows. Such copolymers have a weight average molecular weight (Mw) of approximately 100,000 ~
Equivalent to 500,000. Further, the amount of the six-membered cyclic acid anhydride unit (a) formed can be adjusted by changing the heat treatment conditions of the reaction mixture, ie, the degree of pressure reduction, heating temperature, heating time, etc. The glass fiber of component (B) used in the resin composition of the present invention may be the glass fiber used in ordinary FRTP (glass fiber reinforced thermoplastic resin),
Among these, E glass with a thickness of about 8 to 20 μm is suitable. There are no particular restrictions on the coupling agent used for this treatment of glass fibers, but silane-based ones are preferred, and glass fibers treated with aminosilane have a better reinforcing effect than those treated with other coupling agents. It was hot. The shape of the glass fibers may be chopped strands or rovings, dispersed pellets, or so-called long fibers contained in the extrusion axis direction of the resin composition pellets with the same length as the pellets. Pellet may also be used. The copolymer of component (A) in the resin composition of the present invention and
Regarding the content ratio of component (B) with glass fiber, (A)
It is necessary that component (B) be present in the range of 5 to 100 parts by weight per 100 parts by weight of the component. The resin composition of the present invention thus obtained may contain a colorant, a mold release agent, an external lubricant,
It can be molded into a predetermined shape at a resin temperature of 200 to 300°C, preferably 240 to 280°C, by adding conventional molding aids such as weatherability improvers and antioxidants. This molding can be carried out not only by injection molding but also by any arbitrary step such as extrusion molding or compression molding. The glass fiber reinforced thermoplastic resin composition of the present invention includes: (1) various FRTPs (ABS-GF, PP-GF, PA-
(GF, PC-GF, etc.) has high rigidity and high tensile strength, (2) has a heat deformation temperature of 115℃ or higher, and has an unprecedentedly high practical heat resistance temperature; (3) ) It has excellent cold and heat cycle resistance, (4) It has excellent chemical resistance, especially oil resistance, and (5) It has a lower molding shrinkage rate than that of crystalline resin because it is a non-crystalline glass fiber reinforced resin. (6) Like AS-GF resin, it is easy to mold, and there is a wide range of molding conditions to choose from. (7) Usage Although it is a relatively inexpensive resin composition considering the monomer composition of copolymerization, its performance is comparable to that of engineering resin FRTP.
It has the following characteristics: Therefore, the glass fiber-reinforced thermoplastic resin composition of the present invention can be used particularly in recent years as the shape of automobiles has become more streamlined and the area of window glass has become larger due to the demand for reduced fuel consumption during driving. As temperatures rise, there is a need to improve the practical heat resistance of various automobile interior parts, so it is advantageously used for such molded parts. In particular, it is suitable for use in instrument panels, which are large automotive interior parts to which stereos, speedometers, etc. are attached, since the above-mentioned characteristics can be utilized. Furthermore, when conventional AS-GF resin is used for a line flow fan in a dual-purpose air conditioner, the line flow fan may be deformed due to lack of practical heat resistance when hot air is emitted; however, the resin composition of the present invention When the line flow fan was used, there was no deformation of the line flow fan, and it was confirmed that it was sufficiently durable for practical use. Furthermore, when the resin composition of the present invention is used for various household parts, such as those used in compact products such as the so-called "light, thin, short, and small" products in recent years,
The reliability of the parts is further improved. From this point of view, the glass fiber reinforced thermoplastic resin composition of the present invention has extremely high practical value. Next, the present invention will be explained in more detail with reference to Examples. In addition, in the physical properties in each example, JIS and
Properties not specified in ASTM were determined according to the method shown below. (1) Glass fiber content Sample each type of FRTP, dissolve it in a solvent (for example, methyl ethyl ketone for the product of the present invention), separate the insoluble glass fiber and thermoplastic resin, weigh the glass fiber, and calculate its content. Calculate. (2) Cold and heat cycle resistance A flat plate of 150 x 150 mm and 3 mm thickness was molded by injection molding, and the molded product was heated at -30°C x 60°C for 1 hour.
After repeating 5 cycles, each cycle being left for 1 hour, the occurrence of cracks is observed, and those with no cracks are marked with "O", and those with cracks are marked with "x". (3) Chemical resistance A box-shaped molded product of approximately 10cm ^W x 15cm ^L x 7cm ^H was injection molded, the molded product was filled with salad oil, and after being left in an atmosphere at 60℃ for 24 hours, the occurrence of cracks was observed. If there is no crack, mark it as “〇”.
Items where cracks occur are displayed with an "x". (4) Injection mold a flat plate with a molding shrinkage rate of 150 x 150 mm and a thickness of 3 mm.
The shrinkage rate is calculated by comparing the dimensions of the molded article and the corresponding dimensions of the mold. (5) Bubble generation test For a flat molded product with a width of 5 cm and a length of 12 cm, and a gate that restricts the width, the thickness of the molded product is 3 mm, 2 mm, and 1 mm from the gate part perpendicular to the length direction.
Molding a so-called three-stage chip with a change in shape and observing whether or not air bubbles occur in the molded product. If bubbles that can be observed with the naked eye are generated inside the molded product, it is marked "×", and if no bubbles are generated, it is marked "○". Display in . In addition, the resin temperature during molding is 260℃, and the mold temperature is
The standard molding condition is 60℃. Table 1 shows the relationship between the (a) unit/(d) unit weight ratio of the copolymer and the degree of bubble generation.

[Table] Shows raw.
Examples 1-3 Methacrylic acid 11% by weight, methyl methacrylate 45%
A monomer mixture consisting of 44% by weight of styrene and 44% by weight of styrene was dissolved in ethylbenzene, and 1,1-bis(tert-butylperoxy) was added as a polymerization initiator.
- Add 3,3,5-trimethylcyclohexane and continuously feed it to the polymerization vessel, and the reaction rate at about 125℃
Polymerization was carried out until it reached 50%. Next, this reaction mixture was held at 260°C for about 60 minutes while reducing the pressure to 10 mmHg or less to remove the solvent and unreacted monomers, and at the same time cause cyclization by intramolecular condensation of methacrylic acid. methyl unit 35
Weight%, styrene units 45% by weight, methacrylic acid units 1% by weight and formula A copolymer having an average molecular weight of approximately 250,000 and consisting of 19% by weight of six-membered cyclic acid anhydride units was produced. The copolymer thus obtained was extruded in a vented extruder so that the resin temperature reached 260°C, and the copolymer was extruded from the vented part using a quantitative feed device.
Glass fiber chopped strands with a length of mm are added and pelletized, and the glass fiber content is adjusted accordingly.
Glass fiber reinforced thermoplastic resin compositions containing 10, 20 and 30% by weight were obtained. The physical properties of each are shown in Table 2. It is clear from Table 2 that all of the above resin compositions have higher rigidity, toughness, and heat resistance than conventional FRTP, and provide molded products with excellent chemical resistance and dimensional accuracy. I understand. Comparative Examples 1 to 4 70% by weight of styrene units and acrylonitrile units
Using a copolymer with an average molecular weight of about 250,000 and consisting of 30% by weight, FRTP with a glass fiber content of 20% by weight was prepared in the same manner as in Example 2 (Comparative Example 1).
The physical properties of FRTP were measured. The results are shown in Table 2. Similarly, a copolymer with an average molecular weight of about 220,000 consisting of 90% by weight of styrene units and 10% by weight of maleic anhydride units (Comparative Example 2), 92% by weight of styrene units.
A copolymer with an average molecular weight of approximately 250,000 consisting of 8% by weight of methacrylic acid units (Comparative Example 3), 92 styrene units
A copolymer with an average molecular weight of approximately 230,000 (Comparative Example 4) consisting of 8% by weight of acrylic acid units and 8% by weight of acrylic acid units was compounded with glass fibers in the same manner as in Example 2 so that the amount of each glass fiber was 20% by weight in FRTP. decentralized
Created FRTP. Its physical properties are shown in Table 2.

[Table] Examples 4-5, Comparative Examples 5-6 Methacrylic acid 8% by weight, methyl methacrylate 72
Using a monomer mixture (Example 4) consisting of 20% by weight of styrene and a monomer mixture (Example 5) consisting of 34% by weight of methacrylic acid, 46% by weight of methyl methacrylate, and 20% by weight of styrene, Example 1 and After polymerization in the same manner, the reaction mixture was heated and cyclized under reduced pressure to produce a copolymer containing a six-membered cyclic acid anhydride having the composition shown in Table 3. For comparison, the same monomer mixture as in Examples 4 and 5 was polymerized under the same conditions, and the heating time under reduced pressure was shortened, and the results are shown in Table 3 as Comparative Examples 5 and 6. A product in which the ratio of six-membered cyclic acid anhydride units to methacrylic acid units was less than 3 was produced. Glass fibers were added to the thus obtained copolymer in the same manner as in Example 2 so that the amount was 20% by weight based on the resin composition to create a glass fiber-reinforced thermoplastic resin composition. The physical properties of each were measured. The results are shown in Table 3. Table 3 shows that the physical properties, mainly heat resistance, change depending on the content of each monomer unit in the copolymer, and as seen in the comparative example, those with a low cyclization rate are moldable. It can be seen that air bubbles are generated in the product, which not only significantly impairs the product value but also deteriorates various physical properties.

【table】

Claims (1)

[Claims] 1 (A) (B) General formula (R ₁ and R ₂ in the formula are hydrogen atoms or methyl groups) 5 to 85% by weight of six-membered cyclic acid anhydride units, (b)
1 to 80% by weight of methyl methacrylate units, (c) 1 to 65% by weight of aromatic vinyl compound units, and (d) as desired.
100 parts by weight of a copolymer containing 10% by weight or less of methacrylic acid or acrylic acid units and having a weight ratio of (a) units/(d) units of 3 or more, and (B) 5 to 100 parts by weight of glass fiber. A glass fiber reinforced thermoplastic resin composition consisting of: 2. The composition according to claim 1, wherein the copolymer has a weight ratio of (a) units to (d) units of 10 or more. 3. The composition according to claim 2, wherein the copolymer has a weight ratio of (a) units to (d) units of 15 or more.