JP2021102783A - Alloy resin - Google Patents

Abstract

To provide an alloy resin capable of forming a molding excellent in scratch resistance and solvent resistance.SOLUTION: In the alloy resin, a vinyl chloride based resin and a methyl methacrylate based resin are mixed in a mass ratio between 40:60 and 70:30; the pencil hardness measured according to JIS K5600-5-4 is from H to 4H inclusive; and the critical strain ε measured in a solvent resistance test by a bending form method using a jig 100 having a shape obtained such that an elliptic cylinder with a major axis 2a of 254 mm and a minor axis 2b of 76.2 mm is cut into quarters along a face passing through the minor axis and along a face passing through the major axis is 0.45% or more.SELECTED DRAWING: Figure 2

Description

The present invention relates to alloy resins.

Generally, polypropylene, acrylonitrile-butadiene-styrene (ABS) resin, and the like are used as molding resins for injection-molded products and the like. These general-purpose resins are excellent in moldability and cost, but tend to have low surface hardness and inferior scratch resistance. Acrylic resin and hard vinyl chloride resin are known as resins having excellent scratch resistance.

Alloying is known as a method for improving the properties of a resin. Patent Document 1 discloses an alloy resin of a vinyl chloride resin and a methyl methacrylate resin.

Japanese Unexamined Patent Publication No. 61-014246

However, since the methyl methacrylate-based resin has low solvent resistance, it is difficult to obtain an alloy resin having sufficient solvent resistance.

An object of the present invention is to provide an alloy resin capable of obtaining a molded product having excellent scratch resistance and solvent resistance.

The present invention has the following aspects.
[1] A vinyl chloride resin and a methyl methacrylate resin are blended in a mass ratio of 40:60 to 70:30, and the pencil hardness measured in accordance with JIS K5600-5-4 is H or more and 4H or less. An alloy resin having a critical strain ε of 0.45% or more as measured by a solvent resistance test by the bending foam method.

[2] The alloy resin according to [1], wherein the vinyl chloride resin is a rigid vinyl chloride resin.
[3] The alloy resin according to [1] or [2], wherein the methyl methacrylate-based resin has a weight average molecular weight of 10,000 or more and 600,000 or less.
[4] The alloy resin according to any one of [1] to [3], wherein the number average molecular weight of the methyl methacrylate-based resin is 5,000 or more and 300,000 or less.
[5] The alloy resin according to any one of [1] to [4], wherein the melt flow rate of the methyl methacrylate-based resin is 1.0 g / 10 minutes or more and 20 g / 10 minutes or less.
[6] The alloy resin according to any one of [1] to [5], wherein the alloy resin has a tensile strength of 60 MPa or more and 90 MPa or less.

According to the present invention, it is possible to provide an alloy resin capable of obtaining a molded product having excellent scratch resistance and solvent resistance.

It is a perspective view which showed the test piece used for the solvent resistance test. It is a perspective view which showed the state of the solvent resistance test.

[Alloy resin]
In the alloy resin of the present invention, a vinyl chloride resin (hereinafter referred to as "PVC resin") and a methyl methacrylate resin (hereinafter referred to as "MMA resin") have a mass ratio of 40:60 to 70: An alloy resin blended at 30 and having a pencil hardness of H or more and 4H or less and a critical strain ε described later of 0.45% or more.

The pencil hardness of the alloy resin is H or more and 4H or less, preferably 2H or more and 4H or less. When the pencil hardness is at least the above lower limit value, the molded product has excellent scratch resistance. The pencil hardness of the alloy resin can be adjusted by the mass ratio of the PVC resin and the MMA resin or the like.
The pencil hardness of the alloy resin is measured according to JIS K5600-5-4.

The critical strain ε of the alloy resin is 0.45% or more, preferably 0.70% or more, and more preferably 1.00% or more. When the critical strain ε of the alloy resin is at least the above lower limit value, the solvent resistance is excellent. The larger the critical strain ε, the better.
The critical strain ε of the alloy resin can be adjusted by the mass ratio of the PVC resin and the MMA resin or the like.
The critical strain ε of the alloy resin is measured by the solvent resistance test shown below.

(Solvent resistance test)
The solvent resistance test by the bending foam method will be described below.
As shown in FIG. 1, a rectangular plate-shaped test piece 10 having a thickness of 1.5 mm, a width of 30 mm, and a length of 125 mm is molded by an injection molding method and stored in a desiccator for one day.
As shown in FIG. 2, a jig 100 having an elliptical column having a major axis 2a of 254 mm and a minor axis 2b of 76.2 mm cut into 1/4 on a surface passing through the minor axis and a surface passing through the major axis is shortened. The shaft (b = 38.1 mm) is installed in the vertical direction, the long axis (a = 127 mm) is in the horizontal direction, and the curved surface 110 is on the horizontal plane.
A band-shaped gauze 20 containing disinfectant ethanol (76.9 to 81.4% by volume at 15 ° C.) extends in the length direction of the test piece 10 at the center of the upper surface of the test piece 10 after storage in the width direction. The gauze 20 on the test piece 10 is covered with the film 30. The first edge 10a of the test piece 10 in this state in the length direction is aligned with the edge 110a on the short axis side of the curved surface 110 of the jig 100, and the lower surface of the test piece 10 is in close contact with the curved surface 110 of the jig 100. With the test piece 10 curved as described above, the test piece 10 is allowed to stand for 24 hours under the conditions of 23 ° C. and 50% RH. The test piece 10 after standing is removed from the jig 100, and the distance between the end of the crack formed in the test piece 10 closest to the first edge 10a and the first edge 10a in the length direction is d (mm). ), And the critical strain ε (%) is calculated from the following equation (1). The above measurement was performed on three molded test pieces, and the average value (%) of the critical strain ε was determined.

However, in the formula (1), t is the thickness (mm) of the test piece 10.

As another test jig, a jig having a convex curved surface is used, the test piece is placed on the jig in a bent state along the convex curved surface, and both end portions of the test piece are fixed with fasteners. .. By fixing the test piece in a bent state on the convex curved surface of the jig, 0.15%, 0.30%, 0.45%, 0.60%, 1.00% can be obtained on the surface of the test piece. There is also a method of testing with distortion.

The tensile strength of the alloy resin is preferably 60 MPa or more and 90 MPa or less, and more preferably 62 MPa or more and 80 MPa or less. When the tensile strength of the alloy resin is at least the lower limit of the above range, the pencil hardness of the molded product is improved. When the tensile strength of the alloy resin is not more than the upper limit of the above range, the processability of the molded product is good.
The tensile strength of the alloy resin can be adjusted by injection molding processing conditions and the like.
The tensile strength of the alloy resin is measured in accordance with JIS K7127.

The elongation of the alloy resin is preferably 8% or more and 40% or less, and more preferably 9% or more and 30% or less. When the elongation of the alloy resin is at least the lower limit of the above range, the solvent resistance of the molded product is improved. When the elongation of the alloy resin is equal to or less than the upper limit of the above range, the processability of the molded product is good.
The elongation of the alloy resin can be adjusted by injection molding processing conditions and the like.
The elongation of the alloy resin is measured according to JIS K7127.

The tensile elastic modulus of the alloy resin is preferably 2,000 MPa or more and 3,500 MPa or less, and more preferably 2,500 MPa or more and 3,000 MPa or less. When the tensile elastic modulus of the alloy resin is at least the lower limit of the above range, the pencil hardness of the molded product is improved. When the tensile elastic modulus of the alloy resin is not more than the upper limit of the above range, the economic efficiency of the molded product is good.
The tensile elastic modulus of the alloy resin can be adjusted by the mass ratio of the PVC resin and the MMA resin or the like.
The tensile elastic modulus of the alloy resin is measured in accordance with JIS K7127.

The PVC-based resin is a polymer in which the ratio of repeating units derived from vinyl chloride (hereinafter, also referred to as “vinyl chloride unit”) is more than 50% by mass with respect to all repeating units. The PVC-based resin may be a homopolymer of vinyl chloride, or may be a copolymer of vinyl chloride and a vinyl-based monomer copolymerizable with vinyl chloride. When the PVC-based resin is a copolymer, it may be a random copolymer, a block copolymer, or a graft copolymer.
The PVC-based resin contained in the alloy resin may be one kind or two or more kinds.

The ratio of the vinyl chloride unit in the PVC resin is preferably 75% by mass or more, more preferably 80% by mass or more, further preferably 85% by mass or more, and particularly preferably 98% by mass or more, based on all the repeating units.

The vinyl-based monomer copolymerizable with vinyl chloride is not particularly limited, and examples thereof include fatty acid vinyl esters, acrylates, methacrylates, vinyl cyanide, vinyl ethers, α-olefins, unsaturated carboxylic acids or acid anhydrides thereof. Examples thereof include vinylidene chloride, vinyl bromide, and various types of urethane.

Examples of the fatty acid vinyl ester include vinyl acetate, vinyl propionate, vinyl laurate and the like. Examples of the acrylate include methyl acrylate, ethyl acrylate, butyl acrylate and the like. Examples of the methacrylate include methyl methacrylate and ethyl methacrylate. Examples of vinyl cyanide include acrylonitrile and methacrylonitrile. Examples of the vinyl ether include vinyl methyl ether, vinyl butyl ether, vinyl octyl ether and the like. Examples of the α-olefin include ethylene, propylene and butylene. Examples of unsaturated carboxylic acids or acid anhydrides thereof include acrylic acid, methacrylic acid, maleic anhydride and the like.
As the vinyl-based monomer copolymerizable with vinyl chloride, one type may be used alone, or two or more types may be used in combination.

The average degree of polymerization of the PVC resin is preferably 400 or more and 1200 or less, more preferably 500 or more and 800 or less, and further preferably 550 or more and 700 or less. When the average degree of polymerization of the PVC resin is at least the lower limit of the above range, the pencil hardness is improved. When the average degree of polymerization of the PVC resin is not more than the upper limit of the above range, the moldability is improved.
The average degree of polymerization is measured by JIS K 6720-2.

The vinyl chloride resin may be a hard vinyl chloride resin or a soft vinyl chloride resin, but the hard vinyl chloride resin is used because the surface hardness of the molded product is high and the scratch resistance is excellent. preferable.

The MMA-based resin is a polymer in which the ratio of repeating units derived from methyl methacrylate (MMA) (hereinafter, also referred to as “MMA units”) is 80% by mass or more with respect to all repeating units.
The MMA-based resin may be a homopolymer of MMA, or may be a copolymer of MMA and a (meth) acrylate other than MMA. In addition, (meth) acrylate is a general term for methacrylate and acrylate.
When the MMA-based resin is a copolymer, it may be a random copolymer or a block copolymer.
The MMA-based resin contained in the alloy resin may be one kind or two or more kinds.

The ratio of the MMA unit in the MMA resin is preferably 80% by mass or more, more preferably 90% by mass or more, based on all the repeating units. When the ratio of MMA units is equal to or higher than the lower limit of the above range, the moldability is improved.

Examples of (meth) acrylates other than MMA include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and 2-ethylhexyl methacrylate.
The (meth) acrylate other than MMA used for the MMA-based resin may be one kind or two or more kinds.

The weight average molecular weight of the MMA resin is preferably 10,000 or more and 600,000 or less, and more preferably 20,000 or more and 400,000 or less. When the weight average molecular weight of the MMA resin is at least the lower limit of the above range, the pencil hardness is improved. When the weight average molecular weight of the MMA resin is not more than the upper limit of the above range, the strength is improved.

The number average molecular weight of the MMA resin is preferably 5,000 or more and 300,000 or less, and more preferably 10,000 or more and 200,000 or less. When the number average molecular weight of the MMA resin is at least the lower limit of the above range, the pencil hardness is improved. When the number average molecular weight of the MMA resin is not more than the upper limit of the above range, the strength is improved.
The weight average molecular weight and the number average molecular weight are polystyrene-equivalent average molecular weights measured by gel permeation chromatography.

The melt flow rate (MFR) of the MMA resin is preferably 1.0 g / 10 minutes or more and 20 g / 10 minutes or less, and more preferably 2.0 g / 10 minutes or more and 15 g / 10 minutes or less. When the MFR of the MMA resin is at least the lower limit of the above range, the workability is good. When the MFR of the MMA resin is not more than the upper limit of the above range, the pencil hardness is improved.
The MFR is measured in accordance with JIS K 7210 under the conditions of a load of 37.3 N and a temperature of 230 ° C.

The mass ratio of the PVC resin and the MMA resin is 40:60 to 70:30, preferably 40:60 to 60:40. The higher the proportion of the PVC resin, the better the solvent resistance. The higher the proportion of MMA-based resin, the higher the surface hardness.

The total ratio of the PVC resin and the MMA resin in the alloy resin is preferably 80% by mass or more, more preferably 85% by mass or more, still more preferably 90% by mass or more, based on the total mass of the alloy resin.

The alloy resin of the present invention can be added with additives such as a heat stabilizer, a light stabilizer, a lubricant and a filler, if necessary, as long as the effects of the present invention are not impaired.
The form of the alloy resin of the present invention is not particularly limited, and examples thereof include pellets.

The method for producing the alloy resin of the present invention is not particularly limited, and examples thereof include a method using a conventional injection molding apparatus provided with a screw.

The alloy resin of the present invention described above has excellent scratch resistance and solvent resistance because the mass ratio of the PVC resin and the MMA resin is controlled to a specific ratio and the pencil hardness and the critical strain ε are controlled to be high. Are better.
The use of the alloy resin of the present invention is not particularly limited, and for example, it can be used for injection-molded products used for vehicles, building materials, home appliances, and the like.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following description.
[Pencil hardness]
Pencil hardness was measured according to JIS K5600-5-4.

[Solvent resistance test]
In each example, as shown in FIG. 1, a rectangular plate-shaped test piece 10 having a thickness of 1.5 mm, a width of 30 mm, and a length of 125 mm was molded by an injection molding method and stored in a desiccator for one day.
As shown in FIG. 2, a jig 100 having an elliptical column having a major axis 2a of 254 mm and a minor axis 2b of 76.2 mm cut into 1/4 on a surface passing through the minor axis and a surface passing through the major axis is shortened. It was installed on a horizontal plane so that the shaft (b = 38.1 mm) was in the vertical direction, the long axis (a = 127 mm) was in the horizontal direction, and the curved surface 110 was on the top.
A band-shaped gauze 20 containing disinfectant ethanol (76.9 to 81.4% by volume at 15 ° C.) extends in the length direction of the test piece 10 at the center of the upper surface of the test piece 10 after storage in the width direction. I installed it like this. The gauze 20 on the test piece 10 was covered with a film 30, Polymarap®. The first edge 10a of the test piece 10 in this state in the length direction is aligned with the edge 110a on the short axis side of the curved surface 110 of the jig 100, and the lower surface of the test piece 10 is in close contact with the curved surface 110 of the jig 100. The test piece 10 was allowed to stand for 24 hours under the conditions of 23 ° C. and 50% RH in a curved state. The test piece 10 after standing is removed from the jig 100, and the distance between the end of the crack formed in the test piece 10 closest to the first edge 10a and the first edge 10a in the length direction is d (mm). ), And the critical strain ε (%) was calculated from the above equation (1). The above measurement was performed on three molded test pieces, and the average value (%) of the critical strain ε was determined.
The critical strain ε when the crack generation distance d at a thickness of 1.5 mm was 111 mm or more was set to “1.00 (%) or more”.

[Example 1]
70 parts by mass of TJZ-1230 (trade name, manufactured by Shinetsu Polymer Co., Ltd., ratio of vinyl chloride unit: 87% by mass, average degree of polymerization: 700) as a PVC resin, and Acrypet VH (trade name, Mitsubishi Chemical) as an MMA resin. Made by MMA, MMA unit ratio: 90% by mass, weight average molecular weight: 90,000, number average molecular weight: 50,000, MFR: 2.0g / 10 minutes) 30 parts by mass, by injection molding, alloy resin A plate-shaped molded product (test piece) having a thickness of 1.5 mm, a width of 30 mm, and a length of 125 mm was produced.

[Example 2]
A molded product (test piece) was produced in the same manner as in Example 1 except that the mass ratio of the PVC resin and the MMA resin was changed to 50:50.

[Example 3]
70 parts by mass of TJX-2158 (trade name, manufactured by Shinetsu Polymer Co., Ltd., ratio of vinyl chloride unit: 87% by mass, average degree of polymerization: 550) as a PVC resin, and Delpet 80N (trade name, Asahi Kasei Co., Ltd.) as an MMA resin. Manufactured, MMA unit ratio: 95% by mass, weight average molecular weight: 100,000, number average molecular weight: 60,000, MFR: 6.0 g / 10 minutes) Same as in Example 1 except that 30 parts by mass is used. A molded product (test piece) was prepared.

[Example 4]
A molded product (test piece) was produced in the same manner as in Example 3 except that the mass ratio of the PVC resin and the MMA resin was changed to 50:50.

[Example 5]
A molded product (test piece) was produced in the same manner as in Example 1 except that the mass ratio of the PVC resin and the MMA resin was changed to 40:60.

[Comparative Example 1]
A molded product (test piece) was produced in the same manner as in Example 1 except that the PVC-based resin was 100 parts by mass and the MMA-based resin was not used.

[Comparative Example 2]
A molded product (test piece) was produced in the same manner as in Example 1 except that the MMA-based resin was 100 parts by mass and the PVC-based resin was not used.

[Comparative Example 3]
A molded product (test piece) was produced in the same manner as in Example 3 except that the MMA-based resin was 100 parts by mass and the PVC-based resin was not used.

[Comparative Example 4]
A molded product (test piece) was produced in the same manner as in Example 1 except that the mass ratio of the PVC resin and the MMA resin was changed to 30:70.

Table 1 shows the manufacturing conditions and evaluation results of each example.

As shown in Table 1, the alloy resins of Examples 1 to 5 had high pencil hardness, excellent scratch resistance, and excellent solvent resistance.
In Comparative Example 1 using the PVC resin alone, the pencil hardness was low and the scratch resistance was inferior. In Comparative Examples 2 and 3 using the MMA resin alone and Comparative Example 4 in which the proportion of the PVC resin was low, the solvent resistance was inferior.

10 ... test piece, 20 ... gauze, 30 ... film, 100 ... jig, 110 ... curved surface.

Claims (5)

The vinyl chloride resin and the methyl methacrylate resin are blended at a mass ratio of 40:60 to 70:30, and the pencil hardness measured according to JIS K5600-5-4 is H or more and 4H or less, and the bending foam method is used. The critical strain ε measured by the solvent resistance test is 0.45% or more.
An alloy resin having a melt flow rate of 2.0 g / 10 minutes or more and 15.0 g / 10 minutes or less. The alloy resin according to claim 1, wherein the melt flow rate of the methyl methacrylate-based resin is 2.0 g / 10 minutes or more and 6.0 g / 10 minutes or less. The alloy resin according to claim 1 or 2, wherein the vinyl chloride resin has an average degree of polymerization of 400 or more and 1,200 or less. The alloy resin according to any one of claims 1 to 3, wherein the methyl methacrylate-based resin has a weight average molecular weight of 10,000 or more and 600,000 or less. The alloy resin according to any one of claims 1 to 4, wherein the methyl methacrylate-based resin has a number average molecular weight of 5,000 or more and 300,000 or less.

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