JPH0228256A - Stabilized resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition with stability in melt forming, esp. prevented from yellowing without impairing the excellent characteristic of nylon 46 by incorporating nylon 46 with a specific modified polyolefin. CONSTITUTION:The objective resin composition can be obtained by incorporating (A) 100 pts.wt. of polytetramethyleneadipamide from tetramethylenediamine and adipic acid, or a copolyamide consisting mainly thereof, pref. 2-6 in relative viscosity with (B) 0.1-10 pts.wt. of a modified polyolefin >=60 deg.C in melting point, produced by adding an alpha,beta-unsaturated carboxylic acid or its derivative (pref. maleic anhydride) to a polyolefin consisting mainly of ethylene component and/or propylene component so that the saponification value after modification fall within the range 5-200mg KOH/g and, pref. furthermore (C) 10-50wt.% of glass fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a nylon 46 resin composition with improved thermal stability during hot melt molding such as injection molding.

(Conventional technology) Nylon 46 is an already known polyamide.

For example, Japanese Patent Application Laid-Open No. 149429/1983 discloses a method for manufacturing nylon 46. Nylon 46 also has excellent properties as an engineering plastic.

It is also known to have particularly excellent heat resistance.

For example, its melting point is 295°C, which is not only higher than 220°C for nylon 6 and 260°C for nylon 66, but also higher than 285°C for polyphenylene sulfide. As described above, since nylon 46 has a high melting point, it has excellent heat resistance expressed by heat distortion temperature and solder resistance.

Also, the crystallization rate is high.

Due to the high crystallinity achieved, the molding cycle is short.

Liquidity is also good. It also has high rigidity and excellent abrasion resistance and creep resistance. As described above, nylon 46 has excellent heat resistance and mechanical properties in addition to the excellent chemical resistance of polyamide, and is therefore expected to be used as an engineering plastic in various fields.

However, although nylon 46 has a high heat deformation temperature, on the other hand, its melting point and thermal decomposition temperature are close to each other, and there is a problem in that it tends to decompose during hot melt molding. For this reason, so-called discoloration often occurs on the surface of the molded product during injection molding. In addition, if the decomposition is significant, the occurrence of silver streaks and deterioration of physical properties are observed.

Although nylon 46 has such excellent chemical resistance, heat resistance, and mechanical properties, as described above, it is inferior in stability during hot melt molding, so improvement thereof has been widely desired.

(Problems to be Solved by the Invention) Therefore, the object of the present invention is to improve the stability of nylon 46 during hot melt molding without impairing its excellent properties.

In particular, it is aimed at preventing the occurrence of discoloration.

(Means for Solving the Problems) As a result of extensive research in order to solve the above-mentioned problems with nylon 46, the present inventors have achieved one of the objects of the present invention by blending a specific modified polyolefin into nylon 4G resin. The present invention has been achieved by finding that all of the above are satisfied.

That is, in the present invention, for 46,100 parts by weight of nylon,
KOII
The present invention relates to a stabilized resin composition containing 0.1 to 10 parts of a modified polyolefin having a melting point of 60° C. or higher and having a melting point of 60° C. or higher. It is completely surprising that by blending such a specific modified polyolefin into nylon 46, it is possible to improve the stability during hot melt molding, and in particular to prevent the occurrence of discoloration, without impairing the excellent properties of nylon 46. This finding was discovered for the first time by the present invention.

Nylon 46 used in the present invention includes polytetramethylene adipamide obtained from tetramethylene diamine and adipic acid, and a copolymerized polyamide whose main constituents are polytetramethylene adipamide units. Furthermore, other polyamides may be included as a mixed component to the extent that the properties of nylon 46 are not impaired. The copolymerization component is not particularly limited, and known amide-forming components can be used. Representative examples of copolymerized components include 6-aminocaproic acid, 1
Amino acids such as 1-aminoundecanoic acid, 12-aminododecanoic acid, p-aminomethylbenzoic acid, lactams such as ε-caprolactam and ω-lauryllactam, hexamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2.4/2 , 4.4 - trimethylhexamethylenediamine.

5-methylnonamethylenediamine, mexylylenecyamine, paraxylylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3
, 5,5-trimethylcyclohexane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, aminoethylpiperazine and other diamines and adipic acid. , speric acid, azelaic acid, sebacic acid, dodecanniic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid,
Examples include dicarboxylic acids such as 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, and diglycolic acid.

Other polyamides used as a mixed component include those made of these components.

The method for producing nylon 46 used in the present invention is arbitrary. For example, JP-A No. 56-149430, JP-A No. 5
The method disclosed in JP-A No. 6-149431, JP-A No. 58-83029, and JP-A No. 61-43631, that is, first, a prepolymer with few cyclic end groups is produced under specific conditions, and then this is Method of preparing high viscosity nylon 46 by solid phase polymerization in a steam atmosphere or 2
- There is a method of obtaining it by heating in a polar organic solvent such as pyrrolidone or N-methylpyrrolidone. nylon 4
There is no particular restriction on the degree of polymerization of 6, but 30°C 196°C
% sulfuric acid, relative viscosity at 1 g/dffi is 2.0
Nylon 46 within the range of from 6.0 to 6.0 is preferably used.

The modified polyolefin used in the present invention is a polyolefin containing an ethylene component and/or a propylene component as a main component, and an α,β unsaturated carboxylic acid or a derivative thereof with a saponification value of 5 to 200 mg KOH/g.
It is added in such a range that the melting point is 60°C or higher.

If the unmodified polyolefin that is the raw material for the above-mentioned modified polyolefin has an ethylene component and/or a propylene component as its main component, other components 1 such as butene-1, hexene-1, decene-1,4-methylbutene-1, 4-Methylpentene-1, hexadiene, norbornadiene.

butadiene, isoprene, acrylic acid, methacrylic acid,
Methyl methacrylic acid, sodium acrylate, zinc acrylate, vinyl acetate, glycidyl methacrylate, etc. may be contained in the molecular chain within a range of 40 mol% or less.

Any polyolefin may be used as long as it satisfies the above conditions.9 For example, polyethylene, polypropylene ethylene-propylene copolymer, ethylene-butene-1 copolymer, and ethylene-vinyl acetate copolymer.

Examples include ethylene-acrylic acid copolymer, ethylene-ethyl acrylic acid copolymer, and ethylene-sodium acrylate copolymer. Among these, polyethylene,
Polypropylene, ethylene-propylene copolymer, and ethylene-butene-1 copolymer are preferred because they allow easy grafting of α,β-unsaturated carboxylic acids.

α to be grafted onto the unmodified polyolefin.

Examples of β-unsaturated carboxylic acids or derivatives thereof include acrylic acid, methacrylic acid, efacrylic acid, maleic acid, fumaric acid, and their acid anhydrides or esters, among which maleic anhydride is preferred. .

The amount of unsaturated carboxylic acid or its derivative to be grafted onto the unmodified polyolefin is such that the saponification value after modification is 5 to 2.
00 mg KOH/g.

If the saponification value is less than 5 mg KOtl/g, the stabilizing effect during hot melt molding is not significant, and on the contrary, the occurrence of silver streaks may be promoted. Saponification value is 200mg K
If it exceeds OH/g, gelation may occur during hot melt molding. Therefore, the preferred saponification value is 5 to 200 mg K
OH/g.

The saponification value of the modified polyolefin is determined by dissolving it in xylene and titrating it with KOH. Further, the melting point of the modified polyolefin is preferably 60°C or higher. When the melting point is less than 60'C, workability is poor. The melting point of the modified polyolefin can be determined using a differential thermal analyzer at a heating rate of 10°C/min.

When adding α,β-unsaturated carboxylic acids or derivatives thereof to polyolefins, they may be added as a copolymer by adding them in advance during polymerization of polyolefins, or they may be grafted by conventional methods after obtaining polyolefins. It may be added by converting.

The blending amount of the modified polyolefin is preferably 0.1 to 10 parts by weight based on nylon 46100 weight 0.

If the amount of modified polyolefin blended is less than 0.1 part by weight, the stabilizing effect during hot melt molding is not significant.

If the amount exceeds 10 parts by weight, heat resistance such as heat distortion temperature will decrease, which is not preferable.

The resin composition of the present invention further includes a heat stabilizer,
Additives such as antioxidants, light stabilizers, lubricants, pigments, flame retardants, and plasticizers may also be added. Also fiber reinforcements like glass fibers, metal fibers, potassium titanate whiskers, carbon fibers, and talc.

Filler reinforcing agents such as calcium carbonate, mica, glass flakes, and metal flakes may also be added. In particular, the amount of glass fiber in the resin composition of the present invention is from 10 to 50%.
By adding % by weight, not only the mechanical strength and heat resistance temperature are significantly improved, but also the water resistance is improved, which is preferable in achieving the object of the present invention.

Examples 1-6. Comparative Example 1 Relative viscosity 4 previously vacuum dried at 100°C for 16 hours
．． 0 no naio 746 (Off+Nanda DSM Co., Ltd., 5
TANYLKS-400) and modified polyolefins (Mitsui Petrochemical Industries, Mitsui Hiwax 1105A and 2203A) obtained by adding an acid anhydride to polyethylene were mixed in the proportions shown in Table 1. These are processed using a twin-screw press ratio machine.
Pellets were obtained by extrusion and canting at a temperature of 00°C. Good pellets were obtained in all cases.

Using the obtained pellets, an injection molding machine (8 steel J100S
) The test piece was molded at 300″C.

Discoloration streaks in the molded products were observed for three injection molding cycle times of 20 seconds, 100 seconds, and 200 seconds.

In addition, the heat distortion temperature, toluene swelling degree 5 bending strength, and bending elastic modulus of the test piece molded at a cycle time of 20 seconds were measured. The results thus obtained are listed in Table 1.

(Effects of the Invention) The resin composition of the present invention effectively prevents the occurrence of discoloration during injection molding without impairing the excellent heat resistance, chemical resistance, and mechanical properties of nylon 46. Stability during molding has been greatly improved.

Patent applicant: Unitika Co., Ltd.

Claims (1)

[Claims] (1) For 46,100 parts by weight of nylon, α,β-unsaturated carboxylic acid or a derivative thereof is added to a polyolefin mainly composed of ethylene and/or propylene in an amount such that the saponification value is 5 to 200 mgKOH/g. A stabilized resin composition containing 0.1 to 10 parts by weight of a modified polyolefin having a melting point of 60° C. or higher.