JPH0739540B2 - Materials for molded articles having liquid or gas barrier properties - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a material for a molded article having a liquid or gas barrier property, and more specifically, to a tube, a tank, a strainer, various covers and the like. The present invention relates to a molding material having a liquid or gas barrier property, which is used for fluid treatment such as fluid transfer, fluid storage or excess.

(Prior Art) Polyamide resins are widely used as injection molding materials for parts such as automobiles and electric appliances, in particular, because the molded products have excellent mechanical properties.

However, the polyamide resin has a property of permeating liquids and gases such as water, alcohol, freon gas, and gasoline, which causes various problems. For example, when a nylon tube is used as a Freon tube related to a refrigeration system, there is a problem that the Freon penetrates and the Freon in the apparatus decreases, and when a nylon tank is used as a brake tank in the automobile field, a brake is applied. There arises a problem that water is mixed in the fluid, and when a nylon tank is used as a gasoline tank, there is a problem that water is mixed in gasoline. Further, even when a gasoline tank composed of two or more layers of polyethylene-nylon is used, if the nylon layer is too thin, the gasoline still permeates, causing a problem of not complying with pollution regulations.

In order to solve such a problem, attempts have been made to satisfy the standard by laminating a plurality of resins each having a different barrier property. However, these also have a problem that the process for producing a molded product is complicated, and a sufficiently satisfactory barrier property cannot be obtained.

(Problems to be Solved by the Invention) Conventional polyamide resin molded products have various problems due to the permeation of liquid or gas as described above.

Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a material for a molded product whose molded product has an excellent liquid or gas barrier property.

[Structure of the Invention] (Means and Actions for Solving Problems) The inventors of the present invention maintain the excellent mechanical and thermal properties of a polyamide resin by blending a layered silicate with the polyamide resin. While improving it, it further improves oxygen and gasoline barrier properties (permeation resistance), which are superior to other conventional resins, and also allows relatively poor moisture and alcohol to permeate. The present invention has been completed by finding that the drawbacks can be improved.

The liquid or the material for molded articles having barrier properties of the present invention comprises (A) 100 parts by weight of a polyamide resin or a resin mixture containing a polyamide resin, and (B) one side of 0.002 to 1 μm.
m, thickness is 6 to 20Å, and each is 20Å on average
It is characterized by comprising 0.05 to 10 parts by weight of a layered silicate uniformly dispersed in the component (A) above.

The component (A) constituting the material for molded articles of the present invention is a polyamide resin or a resin mixture containing a polyamide resin.

Polyamide resin is an acid amide bond (-CONH
-), Specifically, ε-caprolactam, 6-aminocaproic acid, ω-enanthlactam,
7-aminoheptanoic acid, 11-aminoundecanoic acid, 9-
Polymers or copolymers obtained from aminononanoic acid, α-pyrrolidone, α-piperidone, etc .; diamines such as hexamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, metaxylylenediamine and terephthalic acid, isophthalic acid Examples thereof include a polymer or copolymer obtained by polycondensing an acid, adipic acid, a dicarboxylic acid such as sebacic acid, or a blend thereof.

The polyamide resin of component (A) has an average molecular weight of 9,000 to 3
Those of 0,000 are preferred.

As the other resin used when the component (A) is a mixture of a polyamide resin and another polymer, polypropylene, AB
Examples thereof include S resin, polyphenylene oxide, polycarbonate, polyethylene terephthalate, and polybutylene terephthalate.

When the component (A) is used as a mixture, the content of the polyamide resin is preferably 40% by weight or more.

The component (B) is a layered silicate. The component (B) is a component that contributes to impart excellent liquid or gas barrier properties to the material for molded articles.

This layered silicate means one unit having a side of 0.002 to 1 μm and a thickness of 6 to 20 Å.

It is preferable that when the layered silicate is dispersed in the component (A), each layer maintains an average interlayer distance of 20 Å or more and is uniformly dispersed. Here, the interlayer distance refers to the distance between the average centers of gravity of the layered silicates, and the term “uniformly distributed” means that the layered silicates are laminated one by one, or on average, the multi-layered objects having five or less layers are parallel to each other. Alternatively, it means a state in which 50% by weight or more, preferably 70% by weight or more are dispersed without forming local lumps randomly or in a state in which parallel and random are mixed.

As a raw material of such layered silicate, a layered phyllosilicate mineral composed of a layer of magnesium silicate or aluminum silicate can be exemplified. Specific examples include montmorillonite, saponite, beidellite, nontronite, hectorite, smectite clay minerals such as stevensite and vermiculite, and halloysite.Even if they are natural, they can be synthesized. It may have been done.

The blending amount of the component (A) and the component (B) is 0.05 to 10 parts by weight with respect to 100 parts by weight of the component (A).
When the blending ratio of the component (B) is less than 0.05 parts by weight, the effect of improving the liquid or gas barrier property is small, and when it exceeds 10 parts by weight, the impact strength and elongation at break at tensile of the molded product are deteriorated, and the polyamide resin is essentially It is not preferable because it impairs the excellent properties inherently possessed.

Dyes, pigments, fibrous reinforcements, particulate reinforcements, plasticizers, heat resistance, foaming agents, flame retardants and the like can be added to the material for molded articles of the present invention in appropriate amounts depending on the purpose.

The method for producing the material for molded articles of the present invention is not particularly limited, and for example, the following method can be applied.

When the raw material of the layered silicate of the component (B) is a multilayered clay mineral, it is contacted with a swelling agent to preliminarily expand the layers to facilitate the incorporation of a monomer between the layers, and then the mixture is mixed with a polyamide monomer to perform polymerization. The method (see JP-A-62-74957) may be used. Alternatively, a polymer compound may be used as the swelling agent, the interlayer may be expanded to 100 liters or more in advance, and the resin may be melt-kneaded with a polyamide resin or a resin containing the polyamide resin and uniformly dispersed.

It is not clear why the molded article obtained from the molded article material of the present invention exhibits excellent liquid or gas barrier properties, but the layered silicate is microscopically dispersed in the polyamide resin to form a liquid or gas. It is considered that it acts to hinder the flow path.

The molding material of the present invention can be applied to various applications that require liquid or gas barrier properties. Applicable applications include gasoline tanks, alcohol tanks,
Examples include fuel tubes, fuel strainers, brake oil tanks, clutch oil tanks, power steering oil tanks, cooler freon tubes, freon tanks, canisters, air cleaners, and intake system parts.

(Example) Example 1 100 g of montmorillonite having an average thickness of one unit of layered silicate of 9.5 Å and an average length of one side of about 0.1 µm was dispersed in 10 water, and 51.2 g of 12-amino was added thereto. 24 ml with dodecanoic acid
Of concentrated hydrochloric acid was added, and the mixture was stirred for 5 minutes and then passed. Further, it was thoroughly washed and then vacuum dried. By this operation, a complex of ammonium 12-aminododecanoate ion and montmorillonite was prepared. The layered silicate content in the composite was 80% by weight. Further, the silicate interlayer distance was 18.0Å as measured by X-ray diffraction of this composite.

Next, 10 kg of ε-caprolactam, 1 kg of water and 100 g of the above complex were placed in a reaction vessel equipped with a stirrer, and stirred at 100 ° C. so that the inside of the reaction system became uniform. The temperature was further raised to 260 ° C., and the mixture was stirred for 1 hour under a pressure of 15 kg / cm ² . Then, the pressure was released and the reaction was carried out under atmospheric pressure for 3 hours while vaporizing water from the reaction vessel. After completion of the reaction, the reaction product taken out in a strand form from the lower nozzle of the reaction vessel was water-cooled and cut to obtain pellets composed of a polyamide resin (average molecular weight 15,000) and montmorillonite. The pellets were dipped in hot water to extract and remove unreacted monomer (about 10%), and then dried in vacuum to obtain a molded article material of the present invention. When the interlayer distance of this material was measured by X-ray diffraction, it was 100Å or more.

(Barrier Property Confirmation Test) The barrier property against freon, water and gasoline was tested by the following method. The results are shown in the table.

Barrier Property to Freon First, the obtained material for a molded product was extruded under the following conditions to prepare a tube having an outer diameter of 1/2 inch and a thickness of 1 mm.

Extrusion molding conditions Extrusion molding machine: manufactured by Japan Steel Works, Ltd. Screw diameter: 30 mm Cylinder setting temperature: C ₁ 220 ℃; C ₂ 255 ℃; C ₃ 255 ℃; Die 25
0 ° C. Cooling condition: water-soluble type, water temperature 15 ° C. Next, the tube was cut into a length of 300 mm and reinforced with a blade (because pressure is applied to the tube after freon injection). Freon R-22 (manufactured by Daikin Industries, Ltd., Daiflon 22) was poured into the tube until it was filled, and the tube was sealed. Perform this injection at -40 ° C, return to room temperature, wipe off the water adhering to the tube, and
The weight after removing the adhering water by drying at 0 ° C. for 22 hours was taken as the initial value. Next, the freon injection tube was dried at 23 ° C. for 2 hours and at 100 ° C. for 22 hours for a total of 24 hours, and the drying operation was repeated for 10 days or more to measure an average amount of freon per unit area per day.

Barrier Property to Moisture The same tube used in the Freon barrier property test was filled with calcium chloride (water absorbent) until it was filled and sealed. The tube is then placed at 40 ° C and 90% relative humidity.
% In an atmosphere of 10% or more, the amount of water per unit surface averaged per day was measured.

Barrier property to gasoline Using the molding material, high-density polyethylene (Hizex8200; manufactured by Mitsui Petrochemical Industry Co., Ltd.) and adhesive (Admer; manufactured by Mitsui Petrochemical Industry Co., Ltd.), Hizex8200 (outer layer) / Admer (intermediate layer) ) / Molding material (inner layer) = 0.6mm thickness / 0.2mm
A bottle of 60 mm (diameter) × 200 mm with a volume of about 500 ml composed of thickness / 0.1 mm thickness was prepared by a three-layer blow molding machine. Inject 250 cc of gasoline into this bottle, seal it 6
It was left for 12 weeks in an atmosphere of 0 ° C. The average amount of gasoline permeated per unit area of gasoline per day was measured by the weight reduction of the entire bottle. Since the gasoline permeation amount of the bottle not including the inner layer is 100 times or more that in the case of including the inner layer, the outer layer and the middle layer do not need to be considered in the measurement result of this time.

(Mechanical Properties of Injection-Molded Article) A molding material was injection-molded under the following molding conditions to prepare a test piece for measuring mechanical properties. The following tests were conducted on this test piece. The results are shown in the table.

Injection molding conditions Injection molding machine: Toshiba Machine Co., Ltd. IS-80 Cylinder set temperature: C ₁ 240 ℃; C ₂ 250 ℃; C ₃ 250 ℃; C ₄ (nozzle) 250 ℃ Injection pressure: 600kg / cm ² gold Mold temperature: 88 ℃ Injection time: 10 seconds Cooling time: 20 seconds Mechanical property measurement method Tensile yield strength: ASTM-D-638 Elongation at break: ASTM-D-638 Bending strength: ASTM-D-790 Bending Elastic Modulus: ASTM-D-790 All tests were conducted at 23 ° C. in an absolutely dry state.

Example 2 A molding material was obtained in the same manner as in Example 1 except that the amount of the composite prepared in Example 1 was 200 g, and each measurement was performed. The results are shown in the table.

Example 3 A molding material was obtained in the same manner as in Example 1 except that the amount of the composite prepared in Example 1 was changed to 500 g, and each measurement was performed. The results are shown in the table.

Comparative Example A molding material was obtained in the same manner as in Example 1 except that montmorillonite was not used, and each measurement was performed. The results are shown in the table. The display shows that the smaller the transmittance, the better the barrier property.

[Effect of the Invention] With the molding material of the present invention, a molded article having excellent barrier properties against liquids and gases can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takezumi Nishio 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd. 1 Toyota Central Research Institute Co., Ltd. (56) Reference JP 62-74957 (JP, A) JP 51-109998 (JP, A) JP 2-29457 (JP, A) JP 2- 29458 (JP, A)

Claims (1)

[Claims] (1) 100 parts by weight of a polyamide resin or a resin mixture containing a polyamide resin, and (B) a side of 0.002 to 1 μm and a thickness of 6 to 20 Å, each separated by an average of 20 Å or more. A material for a liquid or gas barrier molded article, which comprises 0.05 to 10 parts by weight of a layered silicate uniformly dispersed in the component (A).