JPH044249A - Reinforced resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition giving a molded article having decreased warpage without deteriorating various excellent properties of base resin by compounding a glass-fiber reinforced polybutylene terephthalate with a specific kind of polymer, a flaky inorganic filler and a powdery inorganic filler. CONSTITUTION:The objective composition contains (A) 40-80wt.% of a polymer mixture composed of (A1) 55-95 pts.wt. of polybutylene terephthalate and (A2) 45-5 pts.wt. of one or more polymers selected from styrene polymer, methyl methacrylate polymer and polycarbonate, (B) 3-35wt.% of glass fiber, (C) 5-25wt.% of a flaky inorganic filler preferably having a thickness of 0.5-20mum and an aspect ratio of 10-80, (D) 5-42wt.% of a powdery inorganic filler preferably having a particle diameter of 1-30mum and, as necessary, (E) 3-20wt.% of a bromine-based polymeric flame-retardant and (F) 1-10wt.% of an antimony compound.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an inorganic filled reinforced resin composition having excellent mechanical properties, thermal properties and moldability.

[Prior Art] A glass fiber reinforced material of polybutylene terephthalate exhibits less change in physical properties in a hygroscopic state than a glass fiber reinforced material of nylon resin. In addition, polybutylene terephthalate has a much lower melting temperature and secondary transition temperature than polyethylene terephthalate, so the crystallization temperature of the glass fiber reinforcement is low and there is no need to add a crystal nucleating agent.
It is recognized that crystallization is sufficiently promoted even at a low mold temperature of 100° C. or less, and there are few problems in the molding process.

In this way, glass fiber reinforced polybutylene terephthalate does not have many of the problems that glass fiber reinforced materials such as nylon and polyethylene terephthalate, which have traditionally been typical thermoplastic engineering plastics, have. It is expected to continue to grow as an engineering plastic because it has well-balanced performance in general resin properties such as properties, heat resistance, moldability, and hygroscopicity.

However, glass fiber reinforcement of polybutylene terephthalate is difficult to overcome due to the shrinkage stress caused by the crystallization of the polymer when the molten resin solidifies in the mold during the injection molding process, and the glass fibers or their arrangement that try to prevent this. Since the internal stress state generated in the molded product due to the interaction differs depending on the location of the molded product, warpage occurs in the molded product taken out from the mold, significantly reducing its commercial value. Therefore, it has the disadvantage that it cannot be used in fields that require dimensional or morphological stability. This type of problem is a phenomenon that is more or less commonly observed in glass fiber reinforced resins of crystalline polymers, but this problem is particularly noticeable in glass fiber reinforced materials of polybutylene terephthalate. For example, 3m
Quite large warpage is observed in plate-shaped molded products with a thickness of less than m, molded products with thickness changes, and molded products with complicated shapes. This warpage can be reduced by reducing the amount of glass fiber added, but this is not appropriate because the reinforcing effect of the glass fiber also decreases.

As a prior art technique aimed at reducing this warpage, Japanese Patent Publication No. 19697/1983 discloses a technique of blending non-grade resin, glass fiber, and particulate inorganic filler with polybutylene terephthalate. However, although warpage can be considerably reduced by using this composition, it is still not possible to obtain a molded article with sufficiently low warpage.

[Problem to be solved by the invention]

As a result of intensive studies to solve this problem, the inventors of the present invention found that, in order to improve the warpage of molded products without impairing the excellent resin properties of glass fiber-reinforced polybutylene terephthalate, the inventors of the present invention have developed a method using various inorganic fillers in addition to glass fiber. When we tried adding a polymer of The effect of reducing warpage by using a granular inorganic filler and a particulate inorganic filler in combination has a synergistic effect, and as a result, warpage can be significantly reduced with almost no deterioration of mechanical properties. We have arrived at the heading Invention.

[Means to solve the problem]

That is, the present invention provides a polymer comprising (A) 55 to 95 parts by weight of polybutylene terephthalate and 45 to 5 parts by weight of at least one kind of polymer selected from the group consisting of a styrene polymer, a methyl methacrylate polymer, and a polycarbonate. 40 to 80% by weight of the combined mixture, (B) 3 to 35% by weight of glass fiber, (C) 5 to 25% by weight of plate-like inorganic filler, and (D) 5 to 42% by weight of particulate inorganic filler. This is a reinforced resin composition made of

Another aspect of the present invention provides (A) 55 to 95 parts by weight of polybutylene terephthalate and 45 to 5 parts by weight of at least one kind of polymer selected from the group consisting of a styrene polymer, a methyl methacrylate polymer, and a polycarbonate. 40-80% by weight of a polymer mixture consisting of (B)
3-35% by weight of glass fiber, (C) 5-35% of plate-shaped inorganic filler
25% by weight, (D) 5 to 42% by weight of particulate inorganic filler,
(E) 3 to 20% by weight of a polymeric brominated flame retardant, and (
F) A reinforced resin composition containing 1 to 10% by weight of an antimony compound.

[Function] As polybutylene terephthalate used in the present invention,
For example, a polymer synthesized from 1,4-butanediol and dimethyl terephthalate can be mentioned. Furthermore, ethylene glycol or 1
．． A polymer co-condensed with a small amount of a third component such as a diol such as 3-propanediol or a dicarboxylic acid other than terephthalic acid may also be used.

In this polybutylene terephthalate, the value of intrinsic viscosity [η] at 25°C in a mixed solvent of equal amounts of tetrachloroethane/phenol is preferably within the range of 0.4 to 20 (6127 g), and 0.6 to 1 .5 (df2/g) is preferred. When [η] is 0.4 or less, mechanical properties such as tensile strength, bending strength, and impact strength tend to decrease, and when [η] exceeds 2.0, melt fluidity tends to decrease. , the molding area tends to become narrower.

The resin composition of the present invention is used as a polymer mixture (A) by mixing the above-mentioned polybutylene terephthalate with at least one polymer selected from the group consisting of a styrene polymer, a methyl methacrylate polymer, and a polycarbonate. . At least one of these polymers works well to reduce warp while maintaining the mechanical properties of polybutylene terephthalate. Note that from the viewpoint of thermal properties, it is particularly preferable to use a styrene polymer or a methyl methacrylate polymer.

The styrenic polymer used in the present invention is a polymer containing at least 50% by weight, preferably 70% by weight or more of styrene, such as polystyrene, styrene/acrylonitrile copolymer, styrene/methyl methacrylate copolymer, styrene/ Methacrylic acid copolymer, styrene/
Methyl methacrylate/acrylonitrile copolymer or the like is used. Methyl methacrylate-based polymers are similarly copolymers containing methyl methacrylate at least 50% by weight or more, preferably 70% by weight or more, such as polymethyl methacrylate, methyl methacrylate/styrene copolymer, methyl methacrylate/methyl acrylate copolymer. Copolymer, methyl methacrylate/acrylonitrile copolymer, etc. are used. Further, as the polycarbonate, for example, a condensation polymer of 4,4'-dioxydiphenylalkane and phosgene can be used.

The mixing ratio of one or more polymers selected from the above and polybutylene terephthalate is 45 to 5 parts by weight to 55 to 95 parts by weight of polybutylene terephthalate.
A total of 100 parts by weight of the polymer mixture (A)].

If the amount exceeds 45 parts by weight, the warpage of the molded product is improved, but the mechanical and thermal properties deteriorate, while if it is less than 5 parts by weight, a sufficient effect in improving the warp cannot be obtained.

The length of the glass fiber (B) blended as a reinforcing agent may be at least the critical length at which the reinforcing effect appears. A longer length is preferable from the point of view of reinforcing effect, but considering workability during mixing and cutting during the molding process, a length of about 0.4 to 6 mm is desirable, and the length of the glass fiber in the final molded product is Saga 0.2
It is preferable that it is 2 mm. The blending amount of glass fiber is 3 to 35% by weight. If it is less than 3% by weight, the mechanical properties will deteriorate, while if it exceeds 35% by weight, the melt fluidity will be greatly reduced.

Examples of the plate-like inorganic filler (C) used in the present invention include flaky inorganic fillers such as glass flakes, mica, and talc. The thickness of the plate-shaped filler is 0.5-2
A range of 0 is preferred. Further, the aspect ratio (length/thickness) is preferably in the range of 10 to 80. If the aspect ratio is small, the mechanical strength of the molded product obtained will be poor, and if the aspect ratio is large, the warp of the molded product obtained will become large. The amount of the plate-shaped inorganic filler added is 5 to 25% by weight. If it is less than 5% by weight, the effect of reducing warpage is not sufficient, and if it exceeds 25% by weight, the appearance and fluidity will deteriorate.

As the particulate inorganic filler (D) used in the present invention, various fillers can be used as long as they do not decompose at the processing temperature. For example, silicic anhydride or silicates such as glass powder, glass peas, talc, clay, calcium metasilicate, and silica powder are particularly preferred, and barium sulfate, titanium oxide, and the like can also be used. It is desirable that the filler be sufficiently dried before use, and if necessary, the surface of the filler may be appropriately treated to achieve adhesion to the resin. The average particle diameter of the particulate inorganic filler is 1 to 30 μm
is desirable. If it is less than 1 μm, the thermal properties tend to deteriorate, and if it exceeds 30 μm, there is little improvement in warpage and melt fluidity tends to decrease. The amount of the particulate inorganic filler added is 5 to 42% by weight. When this amount is less than 5% by weight, the effect of improving warpage is small, and when it exceeds 42% by weight, the mechanical properties are significantly deteriorated.

The reinforced resin composition of the present invention comprising the above-mentioned components (A) to (D) has the excellent resin properties of glass fiber-reinforced polybutylene terephthalate, and is also a reinforced resin composition with less warpage of molded products. It is a thing.

Furthermore, in order to further impart flame retardancy to the resin composition of the present invention, it is preferable to add a polymeric brominated flame retardant (E) and an antimony compound (F).

The polymeric brominated flame retardant (E) used in the present invention includes:
Pentabromobenzyl polyacrylate, pentabromobenzyl polymethacrylate, polytetrabromoxylylene bismethacrylate, brominated polycarbonate, poly(2,4,6-tribromo)styrene, poly(2,4
, 5-tribromo) styrene, brominated crosslinked polystyrene, and the like. Brominated flame retardants that are not polymeric are not preferred because they bleed out. The blending amount of the polymeric brominated flame retardant is 3 to 20% by weight. Contains 3% by weight
If the resin composition is less than 10%, almost no flame retardant effect can be expected. Furthermore, if the amount of the resin composition exceeds 20% by weight, the mechanical strength of the resulting molded product will decrease.

The antimony compound (F) used in the present invention acts as a flame retardant aid for polymeric brominated flame retardants, and includes, for example, antimony trioxide, antimony pentoxide, and sodium antimonate. The amount of antimony compound is 1 to 1
O% by weight. In a resin composition containing less than 1% by weight, the effect of the flame retardant auxiliary agent can hardly be exhibited. Furthermore, if the amount of the resin composition exceeds 10% by weight, the mechanical strength of the resulting molded product will decrease.

Furthermore, additives such as stabilizers against heat and light, dyes and pigments can be added to the reinforced composition of the present invention, if necessary.

When producing the reinforced resin composition of the present invention, for example, sufficiently dried pellet-shaped polybutylene terephthalate, at least one polymer selected from styrene resin, methyl methacrylate resin, and polycarbonate, glass fiber, There is a method in which a plate-like inorganic filler, a particulate inorganic filler, a polymeric bromine-based flame retardant, and an antimony-based compound are mixed in a V-type blender, and then melt-mixed using an extruder to form pellets. . In addition, two types of polymers, inorganic fillers, flame retardants, etc. are mixed and made into pellets,
It is also possible to mix the pellets and glass fibers and directly charge them into the hopper of an injection molding machine without passing them through an extruder, and mold them at the same time as melting and mixing.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

1-10 and 1-4 Thoroughly dried polybutylene terephthalate pellets [η] measured in a mixed solvent of equal amounts of tetrachloroethane/phenol is 0.9 (dβ/g)], polycarbonate, polystyrene, polymethyl methacrylate any one type of polymer, a surface-treated commercially available chopped strand type glass fiber with an average length of 3 mm and a diameter of 13 μm, a plate-shaped inorganic filler, a particulate inorganic filler, and a polymer. A brominated flame retardant and an antimony compound were mixed in the proportions shown in Table 1, and this mixture was put into a 40 mmφ vented extruder and melt-extruded at a cylinder temperature of 240° C. to 260° C. to form pellets.

These pellets were molded into No. 1 dumbbells with a thickness of 3.2 mm using a 5 oz. Each test molded product was manufactured using a three-cavity mold for a test piece and a heat distortion temperature test piece having a thickness of 6.41, and was used to evaluate mechanical properties and thermal properties.

Also, molded products using the same pellets tend to warp10.
Using a 0x100x1 mm flat plate mold, a flat plate with a thickness of 1 mm was molded under the same molding conditions, and the amount of warpage was evaluated. FIG. 1 shows this molded plate 1 and a side gate 2 of 2×2 mm, and the amount of warpage is a value obtained by measuring the height (β) of the center of the molded plate 1 as shown.

The above evaluation results are shown in Table 1. The abbreviations used and details of each component are described below.

PBT = polybutylene terephthalate (mentioned above) PS = polystyrene (product name: Dialex, manufactured by Mitsubishi Monsanto ■) PMMA = polymethyl methacrylate (product name: Niacrivet VH1 manufactured by Mitsubishi Rayon ■) PC = polycarbonate (product name: Nipparex 7025A, manufactured by Mitsubishi Kasei ■) In addition, as "(C) plate-shaped filler" in Table 1, in Examples 1 to 4 and Comparative Example 2, one with an aspect ratio of 15 and a thickness of 2 μm was used, and in Examples 5 to 8, one with an aspect ratio of 2 μm was used. 40 and thickness 6μ
In Examples 9 to 10 and Comparative Example 5, those with an aspect ratio of 26 and a thickness of 3 μm were used.

11-20 and 5-1O As shown in Table 2, pellets were prepared in the same manner except that a flame retardant and a flame retardant aid were further added (but not added in Comparative Example 5), and the mechanical properties and Thermal properties and amount of warp were evaluated, and flame retardancy (UL-94) was also evaluated by molding a 1.6 mm thick combustion test piece.

The evaluation results are shown in Table 2. The abbreviations used and details of each component are described below.

In Example 19 and Comparative Examples 19 and 19.20, those with an aspect ratio of 26 and a thickness of 3 μ were used. In Example 20, those with an aspect ratio of 12 and a thickness of 1 μ were used.

(Left below) PBB-PA = Bendabromobenzyl polyacrylate (Detsui Co., Ltd.) Br-Pst = Brominated cross-linked polystyrene (Product name: E
BR-370FK, manufactured by Kohyo Kagaku Co., Ltd.) Br-Pc = brominated polycarbonate (product name: FG7500, manufactured by Yojin Kasei Co., Ltd.) In addition, as "(C) plate-shaped filler" in Table 2, Examples 11 to 14 and Comparative Example 6, the aspect ratio was 15 and the thickness was 2μ,
In Examples 15 to 18, as is clear from the results shown in Tables 1 and 2, the resin compositions of Examples 1 to 20, which are within the blending range of the present invention, have improved tensile properties and Izot impact strength. The heat deformation temperature is sufficient, and a molded product with a very small amount of warpage can be obtained. Further, from the resin compositions of Examples 11 to 20 to which predetermined flame retardants and flame retardant aids were added, molded articles having better flame retardancy while maintaining good properties can be obtained.

On the other hand, good results were not obtained from the resin compositions of Comparative Examples 1 to 10, which were outside the blending range of the present invention. For example, for the composition of Comparative Example 6 in which glass fiber was blended with polybutylene terephthalate alone, or the composition of Comparative Example 1, 2.6.7 in which only either particulate or plate filler was blended, molding The material warps a lot, and the composition of Comparative Example 6 does not contain flame retardants, so it is not flame retardant. Furthermore, in the composition of Comparative Example 3.8 in which a large amount of particulate filler was blended, the strength of the molded product decreased. Furthermore, in the composition of Comparative Example 4.9 in which polystyrene was blended in excess, the heat resistance of the molded product decreased. Furthermore, as seen in Comparative Example IO, when an excessive amount of flame retardant is blended, the physical properties are significantly deteriorated.

[Effects of the Invention] As explained above, the reinforced resin composition of the present invention can reduce warpage of molded products without impairing various excellent resin properties of glass fiber reinforced polybutylene terephthalate, and can further improve flame retardancy if desired. It is also possible to obtain molded articles.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining evaluation of warping in the example. 1... Molded plate 2... Side gate patent applicant Mitsubishi Rayon Co., Ltd.

Claims (2)

[Claims] (1) (A) A polymer mixture comprising 55 to 95 parts by weight of polybutylene terephthalate and 45 to 5 parts by weight of at least one type of polymer selected from the group consisting of styrene polymers, methyl methacrylate polymers, and polycarbonates. 40 to 80% by weight, (B) 3 to 35% by weight of glass fiber, (C) 5 to 25% by weight of plate-like inorganic filler, and (
D) A reinforced resin composition containing 5 to 42% by weight of a particulate inorganic filler. (2) (A) A polymer mixture comprising 55 to 95 parts by weight of polybutylene terephthalate and 45 to 5 parts by weight of at least one type of polymer selected from the group consisting of styrene polymers, methyl methacrylate polymers, and polycarbonates. 40-80% by weight, (B) 3-35% by weight of glass fiber, (C) 5-25% by weight of plate-like inorganic filler, (D) 5-42% by weight of particulate inorganic filler, (E) Polymer A reinforced resin composition containing 3 to 20% by weight of a type brominated flame retardant and 1 to 10% by weight of (F) an antimony compound.