JPH0786168B2 - Polyamide resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Industrial field of application The present invention is applicable to dimensions such as heat resistance, chemical resistance, mechanical properties, and electrical properties, particularly molding shrinkage, dimensional change after absorption of water, and warp deformation. The present invention relates to a polyamide resin composition having excellent stability.

b. Conventional technology Polytetramethylene adipamide resin (Nylon 4,6
Has excellent heat resistance, toughness, chemical resistance, and sliding characteristics, and is expected to be put to practical use in various applications as a structural material.

However, nylon 4 and 6 have the drawbacks of (1) large shrinkage during molding (2) large dimensional change after water absorption (3) warpage deformation after molding.

Due to the diversified uses of structural materials, molded products tend to be large in size and have a complicated structure, and high dimensional accuracy, rigidity, and heat resistance are required.

Generally, as a method of improving these performances, a method of adding an inorganic powder filler such as calcium carbonate, titanium oxide, magnesium carbonate, silicic acid, and clay is often used, but when such a method is applied to nylon 4 and 6, However, a method of simultaneously improving heat resistance, rigidity and dimensional stability while maintaining the impact resistance of nylons 4 and 6 has been not found yet, which causes deterioration of impact resistance and workability.

c. Problems to be Solved by the Invention As a result of intensive studies to improve the above-mentioned problems of nylons 4 and 6, the present inventors have mixed specific glass fibers in nylons 4 and 6 and further required them. Depending on the composition, the rigidity, heat resistance, dimensional stability, impact resistance, creep properties, sliding properties, and warp deformability of the resin composition can be expected from the components before compounding by using other inorganic fillers in combination. The present invention has been arrived at by obtaining the surprising finding that it is improved.

d. Means for Solving the Problems The present invention includes (a) polytetramethylene adipamide 20 to 92% by weight, (b) glass fibers having an average length of 0.5 mm or more 5 to 70% by weight, and (c) A polyamide resin composition comprising potassium titanate and / or kaolin in an amount of 3 to 72% by weight.

Nylon 4,6 used in the present invention has the following formula _{NH- (CH 2) 4 -NH-} CO- (CH 2) a polyamide consisting essentially of repeating structural units represented by the ₄ -CO.

The manufacturing method is described in, for example, JP-A-56-149430.
56-149431, 58-83029, and Japanese Patent Publication No. 60-28843 can be used.

Also, at least 1.5 to obtain the resin composition according to the present invention,
Relative viscosity of preferably _{2.5 to 5.0} (η _reL : 30% sulfuric acid at 30 ° C)
Nylon with (measured in a solution of 1 g of polymer in 100 ml)
Preference is given to using 4,6.

In the composition of the present invention, the proportion of nylon 4,6 used is 20-9.
It is 2% by weight, preferably 35 to 85% by weight. If it is less than 20% by weight, the molding processability and the molding appearance are significantly deteriorated.
If it exceeds 92% by weight, impact resistance, rigidity, heat resistance and dimensional stability are not sufficiently improved, which is not preferable.

The glass fiber applied to the present invention is a glass roving made of continuous long fiber strands having a diameter of about 3 to 20 μm among glass fibers generally used as a reinforcing material for thermoplastic resins and thermosetting resins, Glass chopped strands, glass yarn or glass wool with a diameter of 0.3 to 30 μm: average length of 0.5 mm or more, preferably 1
.About.20 mm, more preferably 2 to 10 mm.

If the average length of glass fiber is shorter than 0.5 mm, nylon
The impact resistance, heat resistance, rigidity and dimensional stability of 4, 6 are not sufficiently improved, which is not preferable.

The composition and manufacturing method of the glass fiber used in the present invention are not particularly limited, and any one having the above-mentioned shape may be used, but preferably urethane, paraffin,
When the surface treated with an emulsion liquid of a silane coupling agent or the one treated with a chromium-based, silane-based or titanium-based surface-treating agent is used, the dispersibility is improved and the desired quality of the present invention is further improved. You can get

In the polyamide resin composition of the present invention, the amount of glass fiber used is 5 to 70% by weight, preferably 8 to 10% by weight.
It is 60% by weight, more preferably 10 to 50% by weight. If the content of the glass fiber is less than 5% by weight, the effect of improving impact resistance, heat resistance, rigidity and dimensional stability is small, and if it exceeds 70% by weight, the molding processability and the molding appearance are deteriorated.

The inorganic filler in the resin composition of the present invention is potassium titanate and / or kaolin. Particularly, potassium titanate is preferable. When potassium titanate is used, a composition having more excellent sliding characteristics can be obtained.

The proportion of the filler used is 3 to 72% by weight, more preferably 10 to 50% by weight. When it is 3% by weight or more, dimensional stability and warp deformability can be improved, which is preferable. On the other hand, if it exceeds 72% by weight, molding processability, molding appearance and impact resistance are significantly deteriorated, which is not preferable.

When the glass fiber (b) and the inorganic filler are used in combination in the resin composition of the present invention, the composition ratio of the two is preferably in the range of 3/1 to 1/1. Also, these filler compositions and nylon
The composition of 4,6 (a) is preferably 80/20 to 11/89% by weight, and more preferably 15/85 to 70/30% by weight (all 100% by weight in total). When the compounding amount of the mixed composition of the glass fiber and the inorganic filler is within this range, heat resistance, rigidity, dimensional stability, impact resistance, slidability, creep characteristics, warp deformability, etc. and molding processability are obtained. In addition, it is possible to obtain a product having a much better balance of physical properties with the molding appearance.

The method of mixing the respective components of the present invention is not particularly limited, for example, nylon 4,6 and glass fiber, inorganic filler is mixed with a Henschel mixer, tumbler, and further batch kneader, Banbury mixer, Obtained by melt mixing in a single or twin screw extruder.

In the present invention, the method of mixing the glass fiber and nylon 4,6 is not particularly limited, for example, when the glass fiber is a glass chop strand or glass wool about 0.5 mm to 10 mm in length, a heating roll, a Banbury mixer. Alternatively, a method of mechanically kneading with a melt extruder, or a solution mixing method of adding to a solution of nylon 4 and 6 dissolved in a solvent and stirring to uniformly disperse it, and then distilling the melt twice by heating is applied. it can. If the glass fiber is glass roving or glass yarn, nylon is used.
A method of melting 4,6 to uniformly coat their surfaces, dissolving nylon 4,6 in a solvent to create a relatively viscous solution and coating the surface of the glass fiber uniformly, and then removing the solvent. A method such as heating by distillation can be applied.

The uniform polyamide resin composition produced in this manner is crushed or cut so that the average size does not become smaller than 0.5 mm, and directly supplied to various molding machines, or produced. It is re-granulated into pellets by a granulator and then supplied to various molding machines.

In the polyamide resin composition of the present invention, if necessary, other additives such as a stabilizer, a lubricant, a filler, a foaming agent and a foaming auxiliary agent, an antistatic agent, a flame retardant, and a colorant may be used. Is free.

If necessary, the following polymer components may be contained. For example, polybutadiene, butadiene-styrene copolymer, acrylic rubber, ethylene-propylene polymer, EPDM, styrene-butadiene block polymer, styrene-butadiene-styrene block polymer,
Styrene-butadiene so Styrene Radial tereblock polymer, polypropylene, butadiene-acrylonitrile copolymer, ABS resin, AES resin, polyvinyl chloride, polycarbonate, styrene-acrylonitrile copolymer, PET, PBT, polyacetal, epoxy resin, polyfluoride Vinylidene, polysulfone, ethylene-vinyl acetate copolymer, polyisoprene, natural rubber, chlorinated butyl rubber, chlorinated polyethylene, PPS resin, polyether,
Examples thereof include ether ketone, PPO resin, styrene-methyl methacrylate copolymer, and styrene-maleic anhydride copolymer.

Further, the resin composition of the present invention, if necessary, nylon 4,
Polyamides other than 6 may be used in combination. For example, nylon 6, nylon 6,6, nylon 6,10, copolymers of terephthalic acid and trimethylhexamethylenediamine, copolymers of xylylenediamine such as poly (meta-xylylene adipamide) and aliphatic carboxylic acids, etc. Is.

Since the present invention has its excellent properties, automobile engine covers, silencers, brake master cylinders, air ducts, various exteriors, VTR connectors, connectors such as optical fiber connectors, door handles,
We can provide molded products such as bearing retainer, chain tensioner, brake lever, window frame insulation frame, magnet switch, radiator tank, sprocket wheel, windsurfing parts, fishing tackle parts.

e. Examples Examples 1 to 3 Glass fiber chop strands with an average length of 3 mm made from strands of continuous filaments with a diameter of about 13 μm and inorganic fillers and nylon 4,6 in proportions shown in Table-1. At the same time in a tumbler and then using a twin-screw extruder,
Melt mixing was carried out at a cylinder temperature of ˜330 ° C.

The mixture was molded by an injection molding machine to prepare a test piece.

The physical properties of the obtained test piece were evaluated, and the results are shown in Table 1.

From these results, the composition of the present invention shows the physical properties aimed at by the present invention.

Each physical property was evaluated by the following methods.

(Evaluation Method) Deflection Temperature Under Load (HDT): ASTM D648 Load 18.6kg / cm ² Without Annealing Bending Strength, Elastic Modulus: ASTM D790 Bending Speed 15mm / min Izod Impact Strength: ASTM D256 23 ℃ Notched Mold Shrinkage: After Molding The dimensional change in the flow direction after 24 hours was measured.

Test piece 1/2 ″ × 1/5 ″ × 5 ″ Dimensional change after absorbing water: Dimensional change in the flow direction when the humidity is adjusted to 70 ° C × RH65% × 150Hr and about 2% is absorbed Test piece 1/2 ″ × 1/8 ″ × 5 ″ Flow Length: Slab Flow Molding Thickness 2mm 330 ℃ Molding, Injection Pressure 570kg / cm ² Mold Temperature 80 ℃ Warp Deformation: Test Piece 1/2 ″ × 1/8 ″ × 5Bar Use 50 at the end of the test piece 1 as shown in Fig. 1.
The weight 2 of 0 g is placed and left for a predetermined time, and the maximum height of the warp generated at the other end (microscopic reading H-thickness of sample piece t =
Measure the amount of warp deformation (mm). In addition, 3 shows a base.

Molding appearance: The appearance of an oriented plate having a thickness t of 1.6 mm was visually evaluated.

⊚: Glossy and smooth surface.

◯: The gloss is slightly inferior, but the surface is smooth.

Δ: There is no gloss and the surface is slightly rough.

X: There is no gloss and the surface is rough.

Examples 4 and 5 In the same manner as in Examples 1 to 3, resin compositions were prepared with the composition ratios shown in Table 1 and their physical properties were evaluated.

Example 4 shows the target physical properties when kaolin is used instead of the potassium titanate used in Examples 1 to 3. In addition, Example 5 is a case where two kinds of inorganic fillers are used, and shows substantially the same level of physical properties as Example 3 using one kind of inorganic filler.

Comparative Examples 1 to 3 Nylon 4,6 and glass fiber or nylon 4,6 and inorganic filler were mixed in a tumbler at the composition ratios shown in Table 2, and then 300 to 300 by using a twin-screw extruder. Melt mixing was performed under the cylinder temperature condition of 330 ° C.

The obtained resin composition was evaluated in the same manner as in Example 2,
The results are shown in Table-2.

Comparative Example 1 is a case where nylon 4 and 6 alone are used, and the desired physical properties are not shown, which is not preferable.

Further, Comparative Examples 2 and 3 are cases in which one type of glass fiber or one type of inorganic filler is mixed with nylon 4 and 6, as compared with Examples 1 to 3 in which glass fiber and inorganic filler are used in combination,
The heat resistance, rigidity, impact resistance, molding shrinkage ratio, molding processability, molding appearance and warp deformation are unfavorably poor in physical property balance.

Comparative Example 4 With the composition ratio shown in Table 2, that is, a resin composition having a glass fiber content of less than 5% by weight was prepared, and the physical properties thereof were evaluated by the same method as in Example 2; It was found that the rigidity, impact resistance and warp deformation amount were inferior, and the desired physical properties were not obtained, which was not preferable.

Comparative Examples 5 to 7 Resin compositions having a glass fiber content and an inorganic filler content higher than the ranges of the present invention were prepared according to the formulation shown in Table 2, and the physical properties thereof were the same as in Example 2. It was evaluated by.
The results are shown in Table-2.

Both compositions are not preferable because they have poor balance of physical properties such as heat resistance, rigidity, impact resistance, dimensional stability, moldability and molding appearance.

Comparative Example 8 This is a case where a glass fiber and an inorganic filler are used in combination using a polyamide resin other than nylon 4 and 6. That is, nylon 6,6, glass fiber, and an inorganic filler were mixed at the composition ratios shown in Table 2 at that time, and melt-mixed using an extruder at a cylinder temperature of 300 to 330 ° C. The physical properties of the obtained composition were evaluated, and the results are shown in Table 2.

Comparative Example 9 The physical properties of Nylon 6,6 were evaluated, and the results are shown in Table 2.

As is clear from Comparative Examples 8 and 9, in the case of nylon 6,6, the effect of improving the warp deformation amount is small. That is, while the warpage deformation amount of Comparative Example 8 was 0.07 mm, nylon 6,6
The warp deformation amount of Example 2 using nylon 4 and 6 instead of
0.02 mm, the warp deformation amount of Comparative Example 8 is extremely large,
You can see that it has not been improved.

f. Effect of the invention The resin composition according to the present invention has a dimensional accuracy, without significantly impairing the heat resistance, toughness, chemical resistance, and sliding properties of polytetramethylene adipamide (nylon 4,6). The sled deformation has been improved.

Therefore, engine covers, which are important parts of automobiles,
It is extremely useful as a molding material for silencers, brake master cylinders, bearing retainers, etc.

If the warp deformation of the molded product is large, the fitting property at the time of assembling the parts is deteriorated, and there is a possibility that the completed parts cannot be assembled during the assembling process. The resin composition of the present invention, in particular,
Since the warp deformation is improved, the fitting property at the time of assembling the parts is excellent, the productivity and the operability of the finished parts are improved, and it is possible to obtain the precise finished parts with a small gap.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a method for measuring a warp deformation amount of a resin composition according to an example of the present invention. 1 …… Test piece, 3 …… 500g weight, 4 …… Base.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumio Kurihara 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd. (72) Shinichi Kimura 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Japan Synthetic Rubber Co., Ltd. (56) Reference JP 51-50960 (JP, A) JP 50-119058 (JP, A) JP 61-188459 (JP, A) JP 61- 188457 (JP, A) JP 61-188455 (JP, A)

Claims (1)

[Claims] 1. (a) Polytetramethylene adipamide 20
To 92% by weight (b) 5 to 70% by weight of glass fibers having an average length of 0.5 mm or more and (c) 3 to 72% by weight of potassium titanate and / or kaolin 3 to 72% by weight. Composition.