JPH0739541B2 - Glass fiber reinforced thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a glass fiber reinforced thermoplastic resin composition. More specifically, it relates to a glass fiber reinforced thermoplastic resin composition comprising polyamide, polypropylene and glass fibers.

[Prior Art and Problems] Glass fiber reinforced polyamide (hereinafter referred to as PAG) is widely used in the field of industrial parts because it has excellent mechanical strength and heat resistance. However, PAG has drawbacks in strength reduction and dimensional change during moisture absorption due to the hygroscopicity of polyamide, and in moldability and crack resistance due to calcium chloride.

On the other hand, a mixture of polyamide, polypropylene and glass fiber has heretofore been attempted to improve the above-mentioned drawbacks of PAG while maintaining the mechanical strength and heat resistance of PAG (see, for example, JP-A-49). -130947, JP Sho
57-172953). However, in these conventional techniques, the content of polyamide required for maintaining mechanical strength and heat resistance comparable to PAG is as high as 75% by weight or more, so that the effect of improving PAG by the polypropylene contained is not sufficient.

Further, for the purpose of further improving the above-mentioned drawbacks, studies have been made on a polyamide content in a range of 60% by weight or less (for example, JP-A-60-58458).

However, in these conventional techniques, since polypropylene is a matrix component, the mechanical strength is greatly reduced, and it is difficult to use, for example, as a substitute material for PAG.

In order to maintain the mechanical strength and heat resistance comparable to PAG in a mixture of polyamide, polypropylene and glass fiber, it is necessary to form a polyamide matrix. In order to further improve the drawbacks of PAG, the matrix of polyamide must be formed in the range of higher polypropylene content. Also,
There is also a need for better flowability of the composition by using lower viscosity polypropylene. For that purpose, it is very important to consider the characteristics and content ratios and viscosities of polyamide and polypropylene, as well as the mixing method of polyamide, polypropylene and glass fiber.

[Means for Solving the Problems] The inventors of the present invention have found that in a mixture of polyamide, polypropylene and glass fiber, the polyamide forms a matrix in the range in which the content of polypropylene is larger, and the mechanical properties are comparable to those of PAG. PAG while maintaining strength and heat resistance
The combination of the improved strength reduction and dimensional change due to moisture absorption and the mixed dimensions of them were earnestly investigated.

As a result, by examining a composition consisting of a specific polyamide, a specific polypropylene and a glass fiber, PA
The inventors have found a glass fiber reinforced thermoplastic resin composition which is excellent in fluidity and impact resistance and has the drawbacks of PAG improved while maintaining rigidity and heat resistance comparable to G, and arrived at the present invention.

That is, the glass fiber reinforced thermoplastic resin composition of the present invention is modified by grafting (1) (a) 100 parts by weight of crystalline polypropylene with 0.05 to 2.0 parts by weight of an unsaturated carboxylic acid and / or its derivative, Modified polypropylene 25-45 with an intrinsic viscosity of 0.9-1.3 measured in decalin at 135 ° C
% By weight, and (b) the viscosity η _b at the time of melt mixing with the component (a) is
(A) is 0.5 to 1.2 times that (eta _a) component, polyamide 75-55 wt% relative viscosity measured at 96% 1% solution in sulfuric acid is 1.8 to 2.5, and, (c) above ( Glass fiber reinforced thermoplastic resin composition consisting of 5 to 150 parts by weight of glass fiber per 100 parts by weight of component a) + component (b), (2) Melting the above components (a) and (b) After mixing,
The composition according to (1) above, wherein the polyamide obtained by adding the component (c) and further melt-mixing it forms a matrix.

The crystalline polypropylene, which is a raw material of the modified polypropylene in the present invention, has a melt index (ASTM D123
8, 230 ° C., 2160 g) is 0.3 to 30 g / 10 min crystalline homopolymer of propylene, random or block copolymer with ethylene, and a mixture thereof. Ethylene
The propylene copolymer has an ethylene content of 5 parts by weight or less for the random copolymer and 3 to 15 for the block copolymer.
Those which are parts by weight are preferred.

Of these crystalline polypropylenes, a particularly preferred one is a propylene crystalline homopolymer having a melt index of 0.3 to 15 g / 10 min.

An unsaturated carboxylic acid and / or its derivative is used as a raw material monomer for graft modification. Specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, citraconic acid, crotonic acid and the like, maleic anhydride, itaconic anhydride, citraconic anhydride and the like are included. Among these, acid anhydrides such as maleic anhydride and itaconic anhydride are preferable.

The graft modification reaction initiator is not particularly limited as long as it has a half-life of 1 minute and the decomposition temperature for obtaining the half-life is not less than the melting point of the raw material polypropylene and not more than 250 ° C. . If the required decomposition temperature exceeds 250 ° C, the graft reaction may not be performed efficiently.

Examples of such a reaction initiator include hydroperoxide,
Examples include organic peroxides such as dialkyl peroxides and peroxyesters. Examples of the organic peroxide used in the present invention include t-butylperoxybenzoate, cyclohexanone peroxide, 2,5-dimethyl-2,
5-di (benzoylperoxy) hexane, t-butylperoxyacetate, methyl ethyl ketone peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and the like. In use, it can be appropriately selected according to reaction conditions and the like.

The modified polypropylene can also be obtained by mixing crystalline polypropylene, the above-mentioned raw material monomer for graft modification and the above reaction initiator, and melt-mixing in a nitrogen stream or in air, or the crystalline polypropylene can be mixed with toluene. Alternatively, it can also be obtained by dissolving under pressure and heating in xylene and stirring and mixing the above-mentioned raw material monomer for graft modification and the above reaction initiator while dropping.

The melt mixing may be performed using a kneading machine such as a twin-screw extruder, a kneader or a Banbury mixer, but usually a single-screw extruder can be used. The mixing temperature is a temperature above the melting point of the raw material polypropylene, usually about 175 to 280 ° C. The melt-mixing time varies depending on the raw materials and the like, but generally it can be carried out for about 0.5 to 20 minutes.

The addition amount of the raw material monomer for graft modification is 0.05 to 2.0 parts by weight, preferably 100 parts by weight of the raw material polypropylene.
0.1 to 1.0 part by weight, and the reaction initiator is 0.002 to 0.5 part by weight.

If the amount of the above-mentioned monomer is less than 0.05 parts by weight, the effect of modification cannot be obtained. On the other hand, if it exceeds 2 parts by weight, the grafting efficiency of the monomer is extremely lowered and the unreacted monomer is increased, which is not preferable.

The modified polypropylene obtained as described above has a graft ratio of the monomer of 0.03 to 1.0% by weight and a viscosity of 135% in decalin.
Intrinsic viscosity measured at ° C is 0.9 to 1.3, preferably graft ratio is 0.05 to 0.5% by weight and intrinsic viscosity is 1.1 to 1.3.

If the graft ratio is less than 0.03% by weight, the compatibility with the polyamide may decrease and the delamination phenomenon may occur during molding. On the other hand, if it exceeds 1.0% by weight, the effect of improving the rigidity will be lost.

When the intrinsic viscosity exceeds 1.3, the fluidity of the composition decreases, and when it is less than 0.9, the strength of the composition decreases because the molecular weight is low.

The content of modified polypropylene is 25 to 45% by weight, preferably 35 to 45% by weight. When the content is less than 25% by weight, polypropylene has almost no effect of improving the rate of decrease in physical properties upon moisture absorption. On the other hand, when it exceeds 45% by weight, the polyamide may not form a matrix and strength comparable to PAG cannot be maintained.

The polyamide used in the present invention is obtained from ε-caprolactam, 6-aminocaproic acid, ω-enanthlactam, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 9-aminononanoic acid, α-pyrrolidone, α-piperidone, etc. Polymers or copolymers, hexamethylenediamine,
Diamines such as nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, metaxylylenediamine and terephthalic acid, isophthalic acid, adipic acid,
A polymer or copolymer obtained by polycondensation with a dicarboxylic acid such as sebacic acid, or a blend thereof, and having a relative viscosity measured in a 1% solution in 96% sulfuric acid of 1.8 to 2.3, preferably 2.0 to 2.2. Relative viscosity is 2.
When it exceeds 3, the polyamide does not serve as a matrix component, so that the heat resistance is not improved, while when it is less than 1.8, the strength decreases because the molecular weight is low. Specifically, nylon 6, nylon 66, nylon 610, nylon 9, nylon 11, nylon 12, nylon 1212, nylon 6/66 and the like can be exemplified.

This polyamide must have a viscosity (η _b ) when melt-mixed with the above-mentioned modified polypropylene is 0.5 to 1.2 times, preferably 0.7 to 1.0 times the viscosity (η _a ) of the modified polypropylene. If the melt viscosity of the polyamide is less than 0.5 times that of the modified polypropylene, the molecular weight of the polyamide will be low and strength will not be obtained. On the other hand, when it exceeds 1.2 times, the formation of the polyamide matrix is deteriorated.

The term "viscosity" as used herein means an apparent viscosity measured by a Koka type flow tester at a shear rate during melt mixing.

The glass fibers used in the present invention are glass chopped strands, glass rovings, glass milled fibers and the like which are commonly used for resin reinforcement. Those whose surface is treated with a silane compound, for example, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriethoxysilane, and a urethane-based, acrylic-based, or epoxy-based low molecular weight resin, preferable.

In order to obtain the glass fiber reinforced thermoplastic resin composition of the present invention, the modified polypropylene, the polyamide and the glass fiber may be melt-kneaded at the same time, and the resin containing the glass fiber may be used. It is preferable that the glass fibers be added and melt-mixed after the polyamide is melt-mixed. For example, after melt-mixing modified polypropylene and polyamide into pellets, adding glass fibers and melt-mixing again, or using an extruder equipped with a raw material supply port in a cylinder part in addition to a normal raw material supply port, It is preferable to add glass fiber after forming a matrix in the polyamide component in advance, for example, by supplying modified polypropylene and polyamide from the supply port and melt-mixing, and by supplying glass fiber from the supply port of the cylinder part and further melt-mixing. .

The glass fiber reinforced thermoplastic resin composition of the present invention contains an antioxidant, an ultraviolet absorber, a lubricant, a pigment, an antistatic agent, a flame retardant, a plasticizer, a nucleating agent, a dye or a small amount of polyolefins. Good.

[Examples] The present invention will be described in more detail with reference to Examples below.
It will be clear that the invention is not limited to these examples.

The measuring methods used in the examples of the present invention are as follows.

Melt index: ASTM D1238 (230 ℃) Tensile property: ASTM D638 Bending property: ASTM D2584 Izod impact strength: ASTM D256 Notched heat distortion temperature: ASTM D648 18.6kg / cm ² load Tensile strength after immersion in boiling water: boiling test piece After 4.5 hours of immersion, the tensile strength is measured by ASTM D638. Flexural modulus after immersion in boiling water: After the test piece is immersed in boiling water for 4.5 hours, the flexural modulus is measured by ASTM D2548. Appearance: Visually surface gloss, glass fiber The swelling was observed, and a good one was indicated by ◯, an inferior one was indicated by x, and an intermediate one was indicated by Δ.

Example 1 A melt index of 1.0 g / 10 minutes, to 100 parts by weight of a propylene crystalline homopolymer, 0.2 part by weight of maleic anhydride and 0.2 part by weight of t-butylperoxybenzoate were added and melt mixed at 220 ° C. 26% by weight of modified polypropylene (hereinafter MPP-1) having an intrinsic viscosity of 1.1 measured in decalin at 135 ° C. and a relative viscosity of 2.2 measured in a 1% solution in 96% sulfuric acid and shear rate during melt mixing 200 ~
At 400 sec ^-1 , nylon 6 has an apparent viscosity of 0.6 times that of MPP-1 measured with a Koka type flow tester (below.
PA-1) 39% by weight was dry blended with a blender and charged into a normal raw material supply port of an extruder (EXT-1) equipped with a raw material supply port in a cylinder part in addition to a normal raw material supply port.
After melt mixing at 80 ℃, length of 3m from the supply port of the cylinder
35% by weight of chopped strands of glass fiber (hereinafter GF-1) with m, diameter 11μ and surface treatment with γ-aminopropyltriethoxysilane were put into a quantitative feeder, and further melt mixed and granulated to produce pellets. did. After drying the pellets, injection molding was performed at 270 ° C. to prepare a test piece for measuring physical properties.

The results are shown in Table 1 below.

Examples 2 to 4 The same procedure as in Example 1 was repeated except that the compounding amounts of MPP-1, PA-1 and GF-1 were changed as shown in Table 1.

Comparative Example 1 The same procedure as in Example 1 was carried out except that modified polypropylene (hereinafter MPP-2) having an intrinsic viscosity of 0.6 modified with the same amount of maleic anhydride as in Example 1 was used in place of MPP-1.

Comparative Example 2 Instead of PA-1, nylon 6 having a relative viscosity of 3.5 (hereinafter referred to as PA
The same procedure as in Example 1 was carried out except that (2) was used.

Comparative Example 3 The procedure of Example 1 was repeated except that unmodified polypropylene (hereinafter referred to as PP-1) having an intrinsic viscosity of 1.2 was used instead of MPP-1.

Comparative Examples 4 and 5 The same procedure as in Example 1 was carried out except that the compounding amounts of MPP-1, PA-1 and GF-1 were changed as shown in Table 1.

Comparative Example 6 PA obtained by dry-blending 65% by weight of nylon 6 having a relative viscosity of 2.2 and 35% by weight of glass fiber usually used in polyamide, and then melt-blending the mixture.
G.

Comparative Example 7 1% by weight of modified polypropylene having a maleic anhydride graft ratio of 3.0% by weight and an intrinsic viscosity of 1.6 instead of MPP-1 (MPP-1
-3), 28% by weight of a propylene crystalline homopolymer (PP-2) having an intrinsic viscosity of 1.8, 36% by weight of PA-1, and GF
35% by weight of -1 was melt-mixed with EXT-2 (a single-screw extruder having only a normal raw material supply port) in a batch method to produce pellets, and a test piece was prepared in the same manner as in Example 1. Obtained.

[Effects of the Invention] The glass fiber reinforced thermoplastic resin composition of the present invention is a mixture of polypropylene, polyamide and glass fiber, in which the content of the polyamide is smaller, the specific polypropylene, the specific polyamide, and the glass fiber. By manufacturing by melting and mixing, it has rigidity and heat resistance comparable to PAG, and has high levels of oil resistance, impact resistance, and electrical characteristics.

As described above, the composition of the present invention has strength and heat resistance on par with PAG, and has a lower specific gravity than PAG and improved hygroscopicity and crack resistance due to calcium chloride and fluidity with balanced physical properties. Since it has PAG, it is suitable for various applications such as automobile parts field and electric parts field where PAG has been conventionally used.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C08L 51:06) (56) References JP-A-62-220542 (JP, A) JP-A-2 -67360 (JP, A) JP-A-57-172953 (JP, A) JP-A-58-206667 (JP, A)

Claims (2)

[Claims] 1. An unsaturated carboxylic acid and / or its derivative of 0.05 to 100 parts by weight of (a) crystalline polypropylene.
Modified polypropylene 25 which is modified by grafting 2.0 parts by weight and has an intrinsic viscosity of 0.9 to 1.3 measured at 135 ° C in decalin 25
˜45% by weight, and (b) the viscosity η _b when melt-mixed with the component (a) is
(A) is 0.5 to 1.2 times that (eta _a) component, polyamide 75-55 wt% relative viscosity measured at 96% 1% solution in sulfuric acid is 1.8 to 2.5, and, (c) above ( A glass fiber reinforced thermoplastic resin composition comprising 5 to 150 parts by weight of glass fiber with respect to 100 parts by weight of component a) + component (b). 2. A polyamide obtained by melt-mixing the above-mentioned components (a) and (b), then adding the component (c) and further melt-mixing the mixture to form a matrix. The composition according to 1).