JPS5879052A - Polyamide resin with high durability and molding therefrom - Google Patents

Abstract

PURPOSE:Moldings that is formed by mixing a polyhydric alcohol with a polyamide resin and melt-forming the resultant composition with heat, thus being suitably used as pipes for circulating hot water, because of its high water resistance for a long time and high durability without any post-treatment. CONSTITUTION:100pts.wt. of a polyamide resin are mixed with 0.5-10pts.wt. of a polyhydric alcohol that has higher absorbability to the polyamide than water and preferably boils at a higher temperature than the melting point of the polyamide, in particular, preferably diethylene glycol, then they are melted and molded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a highly durable boria 2-d resin and a molded article, which can be exposed to ridges, exposed to direct contact with water or an aqueous liquid, and subjected to a single batch or for many years. Boriamide resin and holamide molded products offer excellent durability in applications where they are used regularly or in applications where water absorption/dehydration is required.

Originally, polyamide resin molded products have 1 mechanical strength.

It is widely used as a functional material due to its excellent heat resistance and chemical resistance, but if it comes into contact with high-temperature water and is used for many years, or if it is subjected to repeated water absorption and drying Durability is not necessarily satisfactory in water absorption and desorption cycles under stress. For example, if a certain Keyaki comes in contact with an aqueous solution containing halogenated gold or natural ice containing various salts for many years.

The surface of polyamide molded products may be eroded, damaging their appearance, and in severe cases, political rifts may occur, resulting in irreversible damage.

Since the straw phenomenon is particularly noticeable under high temperature conditions,
Conventionally, countermeasures have been taken, such as adding various heat-resistant agents such as 撽 compounds or various 熜 stabilizers such as 碢溢 compounds to polyamide resins, but it is difficult to believe that the water resistance and durability of polyamides has been significantly improved. Saimen<.

The effect was insufficient.

The present inventors have delved into the above-mentioned circumstances, and in the process of carefully examining the water resistance of polyamide resins, have discovered a method for improving water resistance by substantially absorbing and swelling polyhydric alcohols into polyamide resins or molded products. has already been presented under the heading (% Application No. 55-85693). This method is difficult to apply since conventional polyamide resins are considered to have poor alcohol resistance; for example, glycol is used as a solubilizing agent for polyamides. I'll take care of it in some way.

In terms of usage, it may not be possible to use it for all purposes.

Depending on the application, the process of treating molded products with polyhydric alcohol prior to use can be extremely complicated.

The present inventors have discovered that water-resistant and
As a result of continuing studies on durable polyamide resins and molded products, we found that a molded product obtained by adding η% of polyhydric alcohol to polyamide resin before molding and mixing in a heating bath was 45J. The present invention was achieved by discovering that the material has excellent water resistance and durability without any after-treatment. That is, the present invention provides a polyamide resin obtained by adding 0.5 to 10 m of a polyhydric alcohol having a substantially low absorption rate to 10011 parts of a polyamide resin, and a polyamide resin obtained by melt-mixing the same. This is a highly durable Boriaod molded product made from a material made of The molded article of the present invention is particularly useful as a hot water circulation pipe in snow melting or heating systems, and furthermore, although it does not constantly come into contact with water or water-based #i liquid, it can be absorbed by repeated use in water and in the atmosphere. It exhibits excellent long-term durability and the effects of the present invention when used in applications where dewatering is intensive, such as fishery materials such as iron-covered materials for cages, fishing nets, and fishing nets.

The present invention involves melting and mixing a specific amount of polyhydric alcohol, which has been known to affect polyamide molded products to reduce weight, dimensions, physical properties, and appearance costs, and even cause melting when heated, into a polyacrylic resin. This is based on the fact that, on the contrary, long-term water resistance and resistance to changes in R environment are significantly improved.

The polyamide resin referred to in the present invention is nylon 6° Thycene 66. Nylon 610. Nylon 11. Nylon 12. The main raw material is a polyamide resin having an amide bond in the main material, such as a copolymer of these or a mixture of 2aI or more of these, and extrusion by mixing with or without mixing each grade additive and/or @ reinforcing material. It is a material that can be subjected to molding, injection molding, blow molding, or molding.

The polyhydric alcohol used in the present invention includes:

Ethylene glycol, propylene glycol, 1゜3-
Propanediol, 1,3-butanediol.

1.4-butanediol, 1.5-bentanediol.

Hexylene glycol, diethylene glycol.

Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, glycerin, etc. have been shown to be effective, but among them, stones that have a high absorption resistance against polyamide resin and a high boiling point. Diethylene glycol, triethylene glycol, 1,4-butanediol, dipropylene glycol and glycerin are % effective.

In this project, the absorption capacity for the target polyamide resin is essential for the use of hyperactive alcohol.
Polyhydric alcohols with low absorption properties tend to be ejected from the surface of the molded product after molding or during actual use, which is not desirable in practice, and the durability of water resistance is unsatisfactory. Although it depends on the expected effect and addition fK, the effect of the present invention is exhibited when using a polyhydric alcohol which has a better water absorption ability than the target polyamide resin.

The polyhydric alcohol is used in an amount of 0.5 to 10 m'jt parts based on polyamide m&100MMh+. If the amount is less than 0.5 parts by weight, sufficient water resistance cannot be obtained, and if it is more than 10 parts by weight, the effect will not improve commensurate with the increase in amount, and the inherent physical properties of polyamide such as rigidity will be significantly degraded, so it may be preferable depending on the application. do not have. In addition, 1 il of polyhydric alcohol with low absorption ridges for the target polyamide resin was added.
When tVc is added, it leaches from the surface of the molded product, which is undesirable as it deteriorates the appearance.

The higher the boiling point of the polyhydric alcohol used, the better;
When a polyhydric alcohol with a low rating is used, it is not preferable because it foams during melt molding. In this case, it is possible to suppress foaming by changing the molding method 9 conditions, etc., but if a polyhydric alcohol with a rating at least higher than the melting point of the target polyamide is used, no special consideration is required.
preferable.

Details of the polyamide produced by the present invention and the method for obtaining molded products are as follows: 1. For example, (1) (1) Polyamide K polyhydric alcohol is added in a predetermined amount, and the mixture is mixed in a tumbler and subjected to direct molding (in this case, In order to ensure uniform impregnation on the pellet, the polyhydric alcohol should be diluted with a low-boiling inert solvent, and after impregnation, the solvent should be dried and removed at a temperature that does not substantially volatilize the polyhydric alcohol.

(You may also try preheating the beret and blending.)
, and (2) melt-mix and pelletize using an extruder such as a blended chip to provide molding. Furthermore, (II+
Polyhydric alcohol in an amount larger than a predetermined amount of wrinkles is melted and kneaded into boria i)' resin to produce a so-called master pellet, which is then blended with a boriamide pellet that does not contain polyhydric alcohol in a predetermined amount and subjected to molding. It is also possible, and there is no particular limitation, and a pipe with an inner diameter of 6 mm and an outer diameter of 7 mm was formed using a molding die from a material in which polyhydric alcohol was tightly melted and dispersed in polyamide packing. . Using this pipe, a model heatin i system was set up in combination with a boiler and IIAw, and groundwater continued to circulate at 80C as a heat medium. 18 Rikitsuki 5t
When we cut out the K nylon pipe and used it as firewood, we found no abnormalities on the inner wall.

Furthermore, when measuring the relative viscosity of pipe sections, almost no caking or decrease in viscosity was observed.

For comparison, the same test was conducted on a pipe molded in the same way without adding the same nylon resin Beret) K polyethylene glycol, and the water resistance of the inner wall of the pipe deteriorated.
The wall had become thinner, and the relative viscosity of the pipe section had decreased to 70% K of the initial test value. In addition, metal ions of various phases such as iron, calcium, zinc, and kabura were detected in the groundwater used in the test.

Example 4 and Comparative Example 3.4 1J! Nylon 6#M fat pellets 100* same as Example 1
Add and mix 5 parts by weight of diethylene glycol to the
Using an injection molding machine with a cylinder diameter of 40cm.

An elastic float part for a hot water tank was molded at a molding temperature of 250° C. and had a cross-shaped cross section with a length of 180 cm, a major axis of 7.5 cm, and a minor axis of 4.5 points. For comparison, the same nylon 6mM FrK was mixed without addition and wollastonite was kneaded and mixed. So-called non-+7-bond nylon was molded in the same way. The first molded product was set on a float mechanism in a muddy water tank at 40 to 70°C, and a 90-day r#11 practical test was conducted.

The material containing diethylene glycol had excellent transferability during molding, and was able to fill the complex lip area with lower injection pressure, resulting in a molded product better than that of the comparative example. In addition, the dimensional change due to water absorption was significantly smaller than that of the comparative example in which no diethylene glycol was added, and was comparable to that of the comparative example #Il: cherry-colored nylon. After 90 days of the practical test, each molded product was subjected to a bending fracture test. The molded products of the comparative examples all suffered brittle fractures, but the examples containing diethylene glycol were only deformed and did not fracture.

Example 5 and Comparative Example 5 Center m + nylon 6 sacrificial beret 100 m 11 same as Example 1
1 ml of diethylene glycol was added to two plates, mixed, and fed to a single-screw extruder with a cylinder diameter of 40 mm.

Melt-spun from a nozzle with a diameter of 0.9 mm and L/D of 1.5, cooled with water, passed through a water drought of 50 C, stretched 4.7 times in an oven at 215 C, and heat-set in an open oven at 280 C. A monofilament having a thread diameter of 0.4 g was obtained.

For comparison, a monofilament was obtained by adding glycol to the same nylon 6 resin, but spinning and drawing it under the same conditions.

Each monofilament is wrapped in a stainless steel frame of length 20A+ with a low tension of 8 degrees so that it does not loosen, and one cycle is immersed in 60cm water for 4 hours and dried indoors for 20 hours @ water swelling. The treatment was repeated 20 times, and the external appearance and tensile strength and elongation were examined. In addition, the same frame material was irradiated with a UV weatherometer for 300 hours, and the outer appearance and tensile strength were examined. The results of the fly resistance and durability of each sample are shown in Table 2.

In Table 1, the bending g* rate of monofilament is the length 3
From the three-point curve ffK with a distance of 2aa between the supports on the sample Q, l■
Calculated from the stress when deflected. In addition, the hydrothermal convergence rate is 10
The shrinkage rate after treatment at 0°C for 30 minutes is shown.

1112 Properties and durability of 1112 t-een 2-ment From Table 2, nylon monofilament containing polyhydric alcohol is highly flexible and has low material cost in tN.
It can be seen that the durability is extremely excellent.

Patent applicant: Unitika Co., Ltd.

Claims (1)

[Claims] 1. Boriaod resin with excellent durability, which is made by adding 0.5 to 10 parts by weight of poly-11111 alcohol, which has a substantial Kmm absorption to the #boriaod resin, to 100 parts by weight of boriaod resin. . 2. The polyamide resin according to item #1!1, in which the polyhydric alcohol has a substantially higher ability to absorb water than the polyhydric resin. 3. The boriaod resin according to claim 1, wherein the polyhydric alcohol has a boiling point higher than the melting point of the boriaod resin. 4. A highly durable boriad molded article formed from a material obtained by melt-mixing the boriad resin according to claim i81, item 1. 5. The molded product according to claim 4, which is made of a material obtained by adding 0.5 to 1031 jiim of at least one of diethylene glycol, triethylene glycol, and glycerin to 100 parts by weight of polyamide resin and melt-mixing the mixture. Dredged fused or heated pipes for heating systems that are resistant to hot water. 6. The pipe described in Patent No. 5 JJ, wherein the polyamide resin is nylon 6. 7. Polyand resin 100Jiltfl with diethylene glycol, triethylene glycol, glycerin, 1
, 4-butanediol, and dipropylene glycol at a concentration of 0.5 to 10 M, and are spun from a material obtained by melt-mixing. Monofilament with excellent properties.