JP2649256B2 - Resin material for automobile canister - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a material for an automobile canister comprising a polymer blend of a polyamide and a polyolefin, and a canister obtained from the material has chemical resistance, Demonstrates excellent heat resistance.

(Prior art) Adsorption of gasoline vaporized in the gasoline tank of the car,
In order to reuse and prevent gasoline from being released into the atmosphere, parts packed with activated carbon are used and are called canisters. A polyamide resin is used for the body of this part because of its excellent gasoline resistance and heat resistance.

(Problems to be Solved by the Invention) However, polyamide resins have poor load salt properties, and cracks may occur in parts due to the adhesion of salt, sealing properties may be reduced, and gasoline vapor may be diffused to the atmosphere. In order to improve the load salt resistance, blending with a polyolefin resin having excellent water absorption is known. However, a simple blend of polyamide and polyolefin, on the contrary, degrades load salt resistance, and also reduces gasoline resistance and heat resistance.

An object of the present invention is to provide a canister material comprising a polyamide and polyolefin composition having excellent chemical resistance such as load salt resistance and gasoline resistance and heat resistance.

(Means for Solving the Problems) The present inventors have studied polyamide and polyolefin resin compositions to achieve the above object,
The present inventors have found that it is necessary that the weight% of the polyamide, the amount of the solvent-insoluble component, and the dispersed particle size of the dispersed phase in the resin composition need to satisfy specific values, respectively, and have accomplished the present invention.

That is, the present invention comprises a polyamide, a polyolefin and a third component for compatibilizing the same, a) the polyamide is 50% by weight or more and 95% by weight in the total composition;
In the following, b) When the resin composition is extracted with decalin and the remaining amount is further extracted with formic acid, the remaining amount of extraction is 30% by weight or less based on the polyolefin. C) Observed on a thin film section obtained from a molded piece. The dispersed phase has a particle size of 5 μm or less.

The polyamide in the present invention is a polymer compound having an acid amide as a repeating unit, for example, nylon 6,
Nylon 11, nylon 12, nylon 46, nylon 66, nylon 610, nylon 612, etc. are used alone or in the form of a copolymer. These polyamides are selected according to the intended use of the composition, but it is preferable to use nylon 6 or nylon 66 for the parts because of their excellent heat resistance and mechanical properties. The molecular weight of these polyamides is not particularly limited, but usually those having a relative viscosity (ηrel) of 2.0 or more are used.

As the polyolefin in the present invention, ethylene,
Propylene, 1-butene, 4-methyl-1-pentene,
Polymers of α-olefins such as 1-hexene, and block or random copolymers thereof are used. Further, a copolymer of the above olefin and a vinyl aromatic compound is also used. Among these olefins, at least 50 mol% of a polypropylene homopolymer or propylene component,
A random or block copolymer with another olefin containing preferably at least 80 mol% is preferred. These polyolefins are selected so that the melt viscosity is close to the viscosity of the polyamide used, and the melt flow index is 1 to 60.
g / 10 minutes is preferred. More preferably, 6 to 30
g / 10 minutes.

As a third component for compatibilizing polyamide and polyolefin, a polyolefin resin containing propylene as a main component or a resin obtained by introducing an acid anhydride group into a copolymer of a vinyl aromatic compound and an olefin is used alone or in combination. Is done.

The polyolefin containing propylene as a main component is a so-called block copolymer or random copolymer of propylene homopolymer or propylene and 20 mol% or more of ethylene, 1-butene, 4-methyl-1-pentene and the like. Or a mixture or blend thereof.

The copolymer of a vinyl aromatic compound and an olefin,
As a vinyl aromatic compound, styrene, α-methylstyrene, vinyltoluene and the like as olefins, and ethylene, propylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1, and octenylene-1 such as α- Olefin or butadiene, isoprene, 1,3
-Refers to a copolymer with a conjugated diene such as pentadiene,
Hydrogenated block copolymers of conjugated diene olefins and vinyl aromatic compounds are also included. in this case,
Depending on the degree of hydrogenation, double bonds may remain so that the degree of unsaturation does not exceed 20% by weight.

To introduce an acid anhydride group, a method of adding an unsaturated acid anhydride such as maleic anhydride, during the polymerization of the polymer, copolymerizing an unsaturated acid anhydride such as maleic anhydride,
Alternatively, there is a method in which an unsaturated carboxylic acid such as acrylic acid or fumaric acid is copolymerized and then dehydrated to form an acid anhydride group. A preferred method is to add maleic anhydride or the like.

Further, as the third component, a liquid olefin oligomer containing an acid anhydride group is used, but it is preferable to use the third component together with the above-mentioned modified polyolefin.

The liquid olefin oligomer is a copolymer of the above-mentioned polyolefin resin or vinyl aromatic compound and olefin or a conjugated diene polymer and a very low molecular oligomer of these hydrogenated products, and is a liquid at room temperature. And containing an acid anhydride group by some means.

Regarding the method of introducing the acid anhydride group, in addition to the above-described method, in the case of a hydrogenated conjugated diene-based polymer, when living polymerizing a conjugated diene compound, ethylene oxide is added,
A method may be used in which polybutadiene having an unsubstituted -OH group is hydrogenated, and then a compound having an acid anhydride group is bound using the -OH group.

In the resin composition of the present invention, the polyamide accounts for 50% by weight or more and 95% by weight or less in the total composition. When the polyamide content is less than 50% by weight, heat resistance is reduced, and stability during running of the automobile cannot be secured. Also,
If the content is more than 95% by weight, the load salt resistance is undesirably reduced. A more preferred polyamide content is 55
% By weight or more and 80% by weight or less.

In the present invention, the third component used as a compatibilizer for polyamide and polyolefin must be blended so that the remaining amount of the resin composition to be extracted is 1% by weight or more and 30% by weight or less based on the polyolefin.

The residual extraction referred to in the present invention means that a resin composition (10.0 g) containing polyamide and polyolefin as main components is first subjected to Soxhlet extraction using decalin (1,000 ml) for 2 hours, and the extraction residue is extracted at 80 ° C. for 8 hours. Dry over. Then
The dried residue (5.0 g) is taken up in formic acid (100 ml) and
Dissolve over time. The insoluble matter is filtered through a glass filter, washed, and dried at 80 ° C. for 8 hours. After cooling, it is weighed, converted into a percentage by weight with respect to the polyolefin, and referred to as a residual extraction amount.

If the extraction residue is large, compatibility is improved, but gasoline resistance and heat resistance are lowered, which is not preferable. If the remaining amount is small, a peeling phenomenon appears, and the load salt resistance is rather deteriorated. A particularly preferable residual amount of extraction is 2% by weight or more and 15% by weight or less.

In the present invention, it is necessary that the resin composition satisfies the requirements described above. In addition to these, the average particle diameter of the dispersed phase in a molded piece obtained from the resin composition is 5 μm or less. . The particle diameter of the dispersed phase as used herein refers to the dispersed phase obtained by using a resin composition containing polyamide and polyolefin as the main components and forming a thin film section (0.06μ) of a molded piece obtained by an ordinary injection molding method, and observing it under an electron microscope. Is the average particle size. The molding conditions at this time vary depending on the polymer constituting the composition, but the resin temperature: the melting point of the polyamide plus the melting point of the polyamide.
10-30 ° C, mold temperature 40-85 ° C, injection pressure 400-550kg / cm ² ,
The residence time in the cylinder is 60 to 180 seconds.

When the particle size is large, delamination is likely to occur, and the load salt resistance is reduced besides,
The average particle size needs to be 5 μm or more. Particularly preferred is 2 μm or less, and most preferred is that most of the observed dispersed phase has a particle size of more than 0.1 μm and 1 μm.
m or less.

The present invention is a material for an automobile canister having the above characteristics, but in addition to the above components, if necessary, glass fiber, an inorganic or organic filler, an antioxidant, an antioxidant, a heat stabilizer, a crystal nucleating agent, Addition of a lubricant or the like is not a problem.

The composition of the present invention can be produced by using a usual melt-kneading machine, for example, an extractor, a Brabender, a roll, etc., but is preferably carried out by a twin-screw extruder having excellent dispersing and kneading functions. preferable.

(Effect of the Invention) The canister material of the present invention is excellent in chemical resistance and heat resistance, and the product reliability of a canister obtained from the material is greatly improved.

Next, the present invention will be described in detail with reference to examples. In addition, the test method in an Example is as follows.

CaCl ₂ resistance: The test piece is immersed in boiling water at 100 ° C. for 24 hours, sprayed with a 5% CaCl ₂ aqueous solution, left in an oven at 100 ° C. for 2 hours, and allowed to cool at room temperature for 1 hour. After repeating this cycle 10 times, the crack depth of the test piece was observed with a microscope.

Gasoline resistance: After immersing the test piece in gasoline at room temperature for 50 hours, the surface state was visually observed.

Example 1 Nylon 66 (manufactured by Asahi Kasei, Leona 1300) and polypropylene (manufactured by Asahi Kasei, Asahi Kasei Polypro M-1600) were used in a weight ratio.
Blend at a ratio of 7: 3. 100 parts by weight of the obtained blend was mixed with a maleic anhydride-modified styrene butylene block copolymer (TAFTEC M-1913, manufactured by Asahi Kasei Corporation, molecular weight 5
10,000, styrene component 32% by weight, maleic anhydride 1.8% by weight
Adduct) and 2 parts by weight of trimellitic acid-modified hydrogenated polybutadiene oligomer [hydrogenated polybutadiene (1,2
Adduct / 1,4 adduct = 9/1, number average molecular weight less than 3,000) OH modified product, trimellitic acid modified product] was mixed and blended. The resulting blend was kneaded and extruded with a twin-screw kneader (PCM30φ, manufactured by Ikegi Iron Works) to obtain a composition.

The remaining amount of the composition after extraction with decalin and further with formic acid was 13% by weight based on polypropylene.

Injection molding the obtained composition to create a test piece,
The CaCl ₂ resistance and gasoline resistance were examined.

The average particle size of the dispersed phase of the test piece was 3 μm.
Met.

Comparative Example 1 Nylon 66 and polypropylene alone were blended at a weight ratio of 7: 3, and a test piece was prepared in the same manner as in Example 1 except that the third component was not added.

The average particle size of the dispersed phase in the test piece was 43 μm.

Table 1 summarizes the results of Example 1 and Comparative Example 1.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C08L 101: 00)

Claims (3)

(57) [Claims] 1. Polyamide, polyolefin and a third component for compatibilizing the same, a) The polyamide is 50% by weight or more and 95% by weight in the total composition.
In the following, b) When the resin composition is extracted with decalin and the remaining amount is further extracted with formic acid, the remaining amount of extraction is 30% by weight or less based on the polyolefin. C) Observed on a thin film section obtained from a molded piece. A material for automobile canisters, wherein the dispersed phase has a particle size of 5 μm or less. 2. The material according to claim 1, wherein the extraction residue is 15% by weight or less. 3. The material according to claim 1, wherein the dispersed phase particle size is 2 μm or less.