Alloy resins and molded products

Abstract

To provide an alloy resin capable of obtaining a molded article excellent in heat resistance and having high hardness, and a molded article excellent in heat resistance and having high hardness using the alloy resin.SOLUTION: The alloy resin is obtained by blending a vinyl chloride-based resin and a methyl (meth)acrylate-based resin, where dots are within a region between a straight line represented by formula (1): S=-7.2+Tg×0.99 and a straight line represented by formula (2): S=-16.2+Tg×0.99 when plotting a glass transition temperature Tg (unit: °C) measured according to JIS K 7121, and a tensile stress S (unit: MPa) measured according to JIS K7161 on a graph having a horizontal axis as a glass transition temperature Tg, and a vertical axis as a tensile stress S, and the glass transition temperature Tg is 75°C or higher. The molded article is molded of the alloy resin.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an alloy resin and a molded article. [Background technology]

[0002] Rigid polyvinyl chloride resins generally have excellent flame retardancy and chemical resistance, and are therefore widely used in applications such as pipes, general building materials, etc. However, rigid polyvinyl chloride resins have the problem of poor heat resistance.

[0003] As a method for improving the heat resistance of polyvinyl chloride resins, it is known to add acrylic heat resistance improving modifiers, ABS resins, etc. as alloys (for example, Patent Document 1). However, the addition of heat resistance improving modifiers or ABS resins, etc., tends to reduce hardness, making it difficult to achieve both heat resistance and hardness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 61-014246 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide an alloy resin which can give a molded article having excellent heat resistance and high hardness, and a molded article using the alloy resin. [Means for solving the problem]

[0006] The present invention has the following configuration. [1] An alloy resin containing a polyvinyl chloride resin and a methyl methacrylate resin, wherein when a glass transition temperature Tg (unit: °C) measured in accordance with JIS K 7121 and a tensile stress S (unit: MPa) measured in accordance with JIS K 7161 are plotted on a graph with the glass transition temperature Tg on the horizontal axis and the tensile stress S on the vertical axis, the alloy resin is within a region between a line represented by the following formula (1) and a line represented by the following formula (2), and the glass transition temperature Tg is 75°C or higher. S = -7.2 + Tg × 0.99 (1) S = -16.2 + Tg × 0.99 (2) [2] The alloy resin according to [1], having a pencil hardness of F or more as measured in accordance with JIS K5600-5-4. [3] The alloy resin according to [1] or [2], wherein the vinyl chloride resin and the methyl methacrylate resin are blended in a mass ratio of 30:70 to 70:30. [4] The alloy resin according to any one of [1] to [3], wherein the glass transition temperature Tg is 75° C. or higher and 100° C. or lower. [5] A molded product obtained by molding the alloy resin according to any one of [1] to [4]. Effect of the Invention

[0007] According to the present invention, it is possible to provide an alloy resin which can give a molded article having excellent heat resistance and high hardness, and a molded article using the alloy resin. [Brief description of the drawings]

[0008] [Figure 1] 1 is a graph in which the glass transition temperature Tg and tensile stress S of the resins used in the molded articles of Examples 1 to 7, Comparative Example 1, and Reference Example 1 are plotted with the glass transition temperature Tg on the horizontal axis and the tensile stress S on the vertical axis. [Diagram 2] 1 is a graph in which the glass transition temperature Tg and the tensile modulus E of the resins used in the molded articles of Examples 1 to 7, Comparative Example 1, and Reference Example 1 are plotted with the glass transition temperature Tg on the horizontal axis and the tensile modulus E on the vertical axis. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Alloy resin] The alloy resin of the present invention is an alloy resin in which a polyvinyl chloride resin (hereinafter referred to as "PVC resin") and a methyl methacrylate resin (hereinafter referred to as "MMA resin") are blended.

[0010] Furthermore, when the glass transition temperature Tg (unit: ° C.) measured according to JIS K 7121 and the tensile stress S (unit: MPa) measured according to JIS K 7161 are plotted on a graph with the glass transition temperature Tg on the horizontal axis and the tensile stress S on the vertical axis, the alloy resin of the present invention is within a region (hereinafter also referred to as "region A") sandwiched between a straight line (hereinafter also referred to as "straight line (1)") represented by the following formula (1) and a straight line (hereinafter also referred to as "straight line (2)") represented by the following formula (2), and has a glass transition temperature Tg (hereinafter also referred to simply as "Tg") of 75° C. or higher. However, "the plot is within region A" includes the case where the plot is on the straight line (1) and the case where the plot is on the straight line (2). S = -7.2 + Tg × 0.99 (1) S = -16.2 + Tg × 0.99 (2) If the plot of Tg and tensile stress S of the alloy resin is within region A and the Tg is 75°C or higher, a molded product with excellent heat resistance and high hardness can be obtained.

[0011] When the glass transition temperature Tg (unit: °C) and the tensile modulus E (unit: MPa) measured according to JIS K7161 are plotted on a graph with the glass transition temperature Tg on the horizontal axis and the tensile modulus E on the vertical axis, the alloy resin is preferably within a region (hereinafter also referred to as "region B") sandwiched between a straight line represented by the following formula (3) (hereinafter also referred to as "line (3)") and a straight line represented by the following formula (4) (hereinafter also referred to as "line (4)"), where "the plot is within region B" includes the case where the plot is on line (3) and the case where the plot is on line (4). E = -156 + Tg × 37.2 (3) E = -491 + Tg × 37.2 ···(4) Since the plot of the Tg and the tensile elastic modulus E of the alloy resin is within region B, it becomes easier to obtain a molded product having excellent heat resistance and high hardness.

[0012] The Tg of the alloy resin is 75°C or higher, preferably 75°C or higher and 105°C or lower, more preferably 75°C or higher and 100°C or lower, and even more preferably 80°C or higher and 90°C or lower. If the Tg of the alloy resin is at least the lower limit value of the above range, the wall thickness of the molded product can be made thinner, resulting in weight reduction. If the Tg of the alloy resin is at most the upper limit value of the above range, it has excellent moldability. The Tg of the alloy resin is measured as the midpoint glass transition temperature by differential scanning calorimetry (DSC) in accordance with JIS K 7121.

[0013] The tensile stress S of the alloy resin is preferably 58 MPa or higher and 97 MPa or lower, and more preferably 63 MPa or higher and 82 MPa or lower. The tensile elastic modulus E of the alloy resin is preferably 2300 MPa or higher and 3750 MPa or lower, and more preferably 2490 MPa or higher and 3190 MPa or lower. The glass transition temperature Tg, the tensile stress S, and the tensile elastic modulus E of the alloy resin can be adjusted by adjusting the average degree of polymerization of the PVC-based resin, the compounding agent, the weight average molecular weight and the number average molecular weight of the MMA-based resin.

[0014] The pencil hardness of the alloy resin is preferably F or higher, and more preferably H or higher. If the pencil hardness is at least the 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-based resin and the MMA-based resin, etc. The pencil hardness of the alloy resin is measured in accordance with JIS K5600-5-4.

[0015] The Vicat softening temperature of the alloy resin is preferably 75°C or higher and 100°C or lower, more preferably 80°C or higher and 95°C or lower. If the Vicat softening temperature of the alloy resin is equal to or higher than the lower limit of the above range, the long-term heat resistance is good and the deformation of the molded product is small. If the Vicat softening temperature of the alloy resin is equal to or lower than the upper limit of the above range, the moldability is good and the tensile stress and tensile modulus are improved. The Vicat softening temperature of the alloy resin is measured by the JIS K 7206 B50 method.

[0016] The deflection temperature under load of the alloy resin is preferably 60°C or higher and 100°C or lower, more preferably 65°C or higher and 95°C or lower. If the deflection temperature under load of the alloy resin is equal to or higher than the lower limit of the above range, the long-term heat resistance is good and the deformation of the molded product is small. If the deflection temperature under load of the alloy resin is equal to or lower than the upper limit of the above range, the moldability is good and the tensile stress and tensile modulus are improved. The deflection temperature under load of the alloy resin is measured according to JIS K7191.

[0017] A PVC-based resin is a polymer in which the proportion of repeating units derived from vinyl chloride (hereinafter also referred to as "vinyl chloride units") exceeds 50% by mass relative to the total repeating units. The PVC-based resin may be a homopolymer of vinyl chloride, or 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 type, or two or more types.

[0018] The proportion of vinyl chloride units in the PVC resin is preferably 75 mass % or more, more preferably 80 mass % or more, further preferably 85 mass % or more, and particularly preferably 98 mass % or more, based on all repeating units.

[0019] The vinyl 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 their acid anhydrides, vinylidene chloride, vinyl bromide, various urethanes, and the like.

[0020] Examples of fatty acid vinyl esters include vinyl acetate, vinyl propionate, and vinyl laurate. Examples of acrylates include methyl acrylate, ethyl acrylate, and butyl acrylate. Examples of methacrylates include methyl methacrylate and ethyl methacrylate. Examples of vinyl cyanides include acrylonitrile and methacrylonitrile. Examples of vinyl ethers include vinyl methyl ether, vinyl butyl ether, and vinyl octyl ether. Examples of α-olefins include ethylene, propylene, and butylene. Examples of unsaturated carboxylic acids or their acid anhydrides include acrylic acid, methacrylic acid, and maleic anhydride. The vinyl monomers copolymerizable with vinyl chloride may be used alone or in combination of two or more.

[0021] 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 even more preferably 550 or more and 700 or less. When the average degree of polymerization of the PVC resin is equal to or more than the lower limit of the above range, the pencil hardness is improved. When the average degree of polymerization of the PVC resin is equal to or less than the upper limit of the above range, the molding processability is improved. The average degree of polymerization is measured according to JIS K 6720-2.

[0022] The vinyl chloride resin may be either a hard vinyl chloride resin or a soft vinyl chloride resin, but the hard vinyl chloride resin is preferred because it provides a molded article with high surface hardness and excellent scratch resistance.

[0023] The MMA-based resin is a polymer in which the proportion of repeating units derived from methyl methacrylate (MMA) (hereinafter also referred to as "MMA units") is 80% by mass or more relative to the total repeating units. The MMA-based resin may be a homopolymer of MMA, or a copolymer of MMA and a (meth)acrylate other than MMA. Incidentally, (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 type or two or more types.

[0024] The proportion of MMA units in the MMA-based resin is preferably 80% by mass or more, more preferably 90% by mass or more, based on all repeating units. When the proportion of MMA units is equal to or more than the lower limit, moldability is improved.

[0025] 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)acrylates other than MMA used in the MMA-based resin may be one type or two or more types.

[0026] The weight average molecular weight of the MMA resin is preferably 10,000 to 600,000, more preferably 20,000 to 400,000. When the weight average molecular weight of the MMA resin is equal to or higher than the lower limit of the above range, the pencil hardness is improved. When the weight average molecular weight of the MMA resin is equal to or lower than the upper limit of the above range, the strength is improved.

[0027] The number average molecular weight of the MMA resin is preferably 5,000 to 300,000, more preferably 10,000 to 200,000. When the number average molecular weight of the MMA resin is equal to or higher than the lower limit of the above range, the pencil hardness is improved. When the number average molecular weight of the MMA resin is equal to or lower 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.

[0028] The melt flow rate (MFR) of the MMA resin is preferably 1.0 g / 10 min or more and 20 g / 10 min or less, more preferably 2.0 g / 10 min or more and 15 g / 10 min or less. When the MFR of the MMA resin is equal to or more than the lower limit of the above range, the processability is good. When the MFR of the MMA resin is equal to or less than the upper limit of the above range, the pencil hardness is improved. The MFR is measured in accordance with JIS K 7210 under conditions of a load of 37.3 N and a temperature of 230°C.

[0029] The mass ratio of the PVC resin to the MMA resin is preferably 30:70 to 70:30, and more preferably 40:60 to 60:40. The higher the proportion of the PVC resin, the higher the solvent resistance. The higher the proportion of the MMA resin, the higher the surface hardness.

[0030] The total proportion of the PVC resin and the MMA resin in the alloy resin is preferably 80 mass % or more, more preferably 85 mass % or more, and even more preferably 90 mass % or more, based on the total mass of the alloy resin.

[0031] Additives such as heat stabilizers, light stabilizers, lubricants, antioxidants, plasticizers, antifouling agents, impact modifiers, colorants, and fillers may be added to the alloy resin of the present invention as necessary, provided that the effects of the present invention are not impaired. The form of the alloy resin of the present invention is not particularly limited, and may be, for example, in the form of pellets.

[0032] The method for producing the alloy resin of the present invention is not particularly limited, and an example of the method is a method using a conventional injection molding machine equipped with a screw.

[0033] The alloy resin of the present invention described above is a blend of a PVC-based resin and an MMA-based resin, and is controlled so that its glass transition temperature Tg and tensile stress S are within a specific region A when the temperature is plotted on a graph. This has resulted in excellent impact resistance and heat resistance.

[0034] [Molded products] The molded article of the present invention is a molded article obtained by molding the alloy resin of the present invention. The molded article of the present invention can adopt a known embodiment except that the alloy resin of the present invention is used. The use of the molded article of the present invention is not particularly limited, and examples thereof include vehicles, building materials, and home appliances. The method for producing the molded article of the present invention is not particularly limited, and examples thereof include injection molding, extrusion molding, and calendar molding. EXAMPLES

[0035] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following description.

[0036] [Glass transition temperature (Tg)] The glass transition temperature was measured as the midpoint glass transition temperature by differential scanning calorimetry (DSC) in accordance with JIS K 7121.

[0037] Tensile Stress The tensile stress S was measured at a tension speed of 50 mm / min after processing into a test piece of type 1B in accordance with JIS K7161.

[0038] [Tensile modulus] The tensile modulus E was measured at a tension speed of 50 mm / min after processing into a test piece of type 1B in accordance with JIS K7161.

[0039] [Pencil hardness] The pencil hardness was measured in accordance with JIS K5600-5-4.

[0040] [Vicat softening point] The Vicat softening point was measured in accordance with JIS K 7206 B50 method.

[0041] [Deflection temperature under load] The deflection temperature under load was measured in accordance with JIS K7191.

[0042] [Example 1] An alloy resin was prepared using 70 parts by mass of TJZ-1232WH (trade name, manufactured by Shin-Etsu Polymer Co., Ltd., proportion of vinyl chloride units: 84 mass%, average degree of polymerization: 700) as a PVC-based resin and 30 parts by mass of ACRYPET VH-001 (trade name, manufactured by Mitsubishi Chemical Corporation, proportion of MMA units: 90 mass%, weight-average molecular weight: 90,000, number-average molecular weight: 50,000, MFR: 2.0 g / 10 min) as an MMA-based resin, and a plate-shaped molded product having a thickness of 4 mm, a width of 200 mm, and a length of 200 mm was produced by injection molding.

[0043] [Examples 2 to 5] Molded articles were produced in the same manner as in Example 1, except that the mass ratio of the PVC-based resin to the MMA-based resin was changed as shown in Table 1.

[0044] [Examples 6 and 7] A molded article was produced in the same manner as in Example 1, except that TJZ-1230WH (product name, manufactured by Shin-Etsu Polymer Co., Ltd., proportion of vinyl chloride units: 87 mass%, average degree of polymerization: 700) was used as the PVC-based resin and the mass ratio of the PVC-based resin to the MMA-based resin was changed as shown in Table 1.

[0045] [Comparative Example 1] A molded article was produced in the same manner as in Example 1, except that the PVC resin was 100 parts by mass and no MMA resin was used.

[0046] [Reference example 1] A molded article was produced in the same manner as in Example 1, except that the amount of MMA resin was 100 parts by mass and no PVC resin was used.

[0047] The manufacturing conditions and evaluation results of each example are shown in Table 1. The glass transition temperature Tg and tensile stress S of the resin used in the molded product of each example are plotted on a graph with the glass transition temperature Tg on the horizontal axis and the tensile stress S on the vertical axis in Fig. 1. The glass transition temperature Tg and tensile modulus E of the alloy resin of each example are plotted on a graph with the glass transition temperature Tg on the horizontal axis and the tensile modulus E on the vertical axis in Fig. 2.

[0048] [Table 1]

[0049] As shown in Table 1, the alloy resins and molded articles of Examples 1 to 7, in which the plots of the glass transition temperature Tg and tensile stress S of the alloy resins are within region A in the graph of Figure 1, had high Tg and excellent heat resistance, and also had high pencil hardness and excellent impact resistance. The molded article of Comparative Example 1, which was made of a PVC-based resin alone and whose plots of the glass transition temperature Tg and tensile stress S are not within region A, had a low Tg and poor heat resistance, and also had a low pencil hardness and poor impact resistance. The molded article of Reference Example 1, which was made of only MMA resin, exhibited sufficient heat resistance and impact resistance, but since it did not contain PVC resin, it is believed that the flame retardancy and chemical resistance were insufficient.

Claims

1. The resin component consists solely of a rigid polyvinyl chloride resin having an average degree of polymerization of 500 to 800 and a methyl methacrylate resin having a weight-average molecular weight of 10,000 to 600,000, The alloy resin is a melt-kneaded product of the rigid polyvinyl chloride resin and the methyl methacrylate resin in a mass ratio of 30:70 to 70:30, The ratio of repeating units derived from vinyl chloride to all repeating units of the rigid vinyl chloride resin is 75% by mass or more, a ratio of repeating units derived from methyl methacrylate to all repeating units of the methyl methacrylate-based resin is 80% by mass or more; When a glass transition temperature Tg (unit: ° C.) measured in accordance with JIS K 7121 and a tensile stress S (unit: MPa) measured in accordance with JIS K 7161 are plotted on a graph with the glass transition temperature Tg on the horizontal axis and the tensile stress S on the vertical axis, the tensile stress S is within a region sandwiched between a line represented by the following formula (1) and a line represented by the following formula (2), The alloy resin has a glass transition temperature Tg of 75° C. or higher. S=-7.2+Tg×0.99...(1) S=-16.2+Tg×0.99...(2)

2. The pencil hardness measured according to JIS K5600-5-4 is F or more. The alloy resin described.

3. The glass transition temperature Tg of claim 1 or 2 is 75° C. or more and 100° C. or less. Roy resin.

4. A molded article obtained by molding the alloy resin according to any one of claims 1 to 3.

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