Resin composition and method for recycling polyvinyl acetal resin

Abstract

In the present invention, obtained is a resin composition in which bleeding of a plasticizer or the like from the composition is controlled even in cases where a raw material containing a large amount of a plasticizer is contained therein, such as an intermediate sheet, and which enables use of a raw material resin in recycling. This resin composition is characterized by: containing a polyolefin-based resin and a poly(vinyl acetal) resin (excluding a poly(vinyl formal) resin) that contains a plasticizer; and further containing at least one type of flexible resin selected from the group consisting of a synthetic rubber, an elastomer and a copolymer olefin resin. When the poly(vinyl acetal) resin containing a plasticizer and the polyolefin-based resin are kneaded, at least one type of flexible resin selected from the group consisting of a synthetic rubber, an elastomer and a copolymer olefin resin is added as a bleeding control agent.

Description

[Technical Field]

[0001] In particular, the present invention relates to a resin composition with controlled bleeding and a method for recycling polyvinyl acetal resin. [Background technology]

[0002] In recent years, laminated glass has been widely used in automobile and aircraft windowpanes, etc., for purposes such as preventing glass fragments from scattering in the event of breakage. Examples of laminated glass include glass sheets integrated by sandwiching an interlayer sheet containing a polyvinyl acetal resin, such as a polyvinyl butyral resin, between glass sheets. Polyvinyl acetal resins for laminated glass interlayer sheets typically contain approximately several tens of percent liquid plasticizer as an essential component for the purposes of viscosity adjustment and sound absorption (see, for example, Patent Document 1). Therefore, to recycle laminated glass sheets available on the market, they must be handled while still containing the plasticizer. However, when the interlayer sheet material is blended with other resins, such as polyolefin resins, and molded, the plasticizer can bleed (bleed out), making it difficult to use the glass as a product. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2010 / 095749 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention solves the above-mentioned problems, and aims to obtain a resin composition that can control bleeding of plasticizers and the like from the composition, even when the resin composition contains a material that contains a large amount of plasticizer, such as an interlayer film sheet, and that enables the raw resin to be utilized particularly in recycling. [Means for solving the problem]

[0005] In order to achieve the above object, the resin composition of the present invention comprises: At least one resin selected from the group consisting of polypropylene resin and polyethylene resin A polyolefin resin, Contains ester compounds with ether bonds in the molecule and a polyvinyl acetal resin (excluding polyvinyl formal resin) containing a plasticizer, Selected from ethylene propylene rubber, ethylene propylene diene rubber, butadiene rubber, styrene butadiene rubber, and isoprene rubber Synthetic rubber, Styrene Butadiene / Butylene / Styrene The composition contains at least one flexible resin selected from the group consisting of elastomers and copolymerized olefin resins, and the content of the polyolefin resin and the Contains plasticizers The weight ratio of polyvinyl acetal resin to polyolefin resin: Contains plasticizers Polyvinyl acetal resin = in the range of 99.9:0.1 to 0.1:99.9 and the weight ratio of the content of the polyvinyl acetal resin containing the plasticizer to the content of the flexible resin (polyvinyl acetal resin containing the plasticizer:flexible resin) is within a range of 20:2.5 to 20:30. It is characterized by the following.

[0006] In the resin composition of the present invention, the plasticizer In the polyvinyl acetal resin containing the above, the weight ratio of the content of the polyvinyl acetal resin to the content of the plasticizer is within the range of polyvinyl acetal resin:plasticizer=3:1 to 2:1. It is preferable.

[0007] In the resin composition of the present invention, the flexible resin is The copolymerized olefin resin may be Ethylene vinyl acetate copolymer Contains It is preferable.

[0008] In the resin composition of the present invention, the polyvinyl acetal resin is preferably at least one selected from the group consisting of polyvinyl acetoacetal and polyvinyl butyral.

[0009] In the resin composition of the present invention, the polyolefin resin and the weight ratio of the content of the polyvinyl acetal resin containing the plasticizer (polyolefin resin:polyvinyl acetal resin containing the plasticizer) is within the range of 99:1 to 75:25. It is preferable.

[0010] The method for recycling a polyvinyl acetal resin of the present invention comprises the steps of: Contains ester compounds with ether bonds in the molecule A method for recycling a polyvinyl acetal resin (excluding polyvinyl formal resin) containing a plasticizer, comprising: , at least one selected from the group consisting of polypropylene resin and polyethylene resin When kneading with polyolefin resin, it acts as a bleeding control agent. Selected from ethylene propylene rubber, ethylene propylene diene rubber, butadiene rubber, styrene butadiene rubber, and isoprene rubber Synthetic rubber, Styrene Butadiene / Butylene / StyreneThe present invention is characterized by the addition of at least one flexible resin selected from the group consisting of elastomers and copolymerized olefin resins. [Effects of the Invention]

[0011] According to the present invention, even when a resin composition contains a material that contains a large amount of plasticizer, such as an interlayer film sheet, it is possible to control the bleeding of plasticizers and the like from the composition, and to obtain a resin composition that allows for the utilization of raw resins, particularly in recycling. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is an infrared spectrum for bleeding evaluation measured using the resin composition of Example 1. [Figure 2] FIG. 2 is an infrared spectrum for bleeding evaluation measured using the resin composition of Example 2. [Figure 3] FIG. 3 is an infrared spectrum for bleeding evaluation measured using the resin composition of Example 3. [Figure 4] FIG. 4 is an infrared spectrum for bleeding evaluation measured using the resin composition of Example 4. [Figure 5] FIG. 5 is an infrared spectrum for bleeding evaluation measured using the resin composition of Example 5. [Figure 6] FIG. 6 shows the infrared spectrum of the resin composition of the reference example, the infrared spectrum of the surface of a test piece made of a PVB interlayer film from process waste, and the infrared spectrum used as a reference for bleeding evaluation. [Figure 7] 7(A) and 7(B) show infrared spectroscopy spectra for bleeding evaluation measured using the resin composition of Comparative Example 1 and Comparative Example 2, respectively. [Figure 8] 8(A) to 8(E) are infrared spectroscopic spectra for bleeding evaluation measured using the resin compositions of Examples 6 to 10. FIG. [Figure 9] 9(A) and 9(B) show infrared spectroscopy spectra for bleeding evaluation measured using the resin compositions of Example 11 and Example 12, respectively. [Figure 10] 10(A) shows the results of gas chromatography mass spectrometry measurement using the resin composition of Comparative Example 3, FIG. 10(B) shows the results of Comparative Example 4, and FIG. 10(C) shows the results of gas chromatography mass spectrometry measurement using the resin composition of Example 13. DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present invention are described in detail below. The resin composition of the present invention contains a polyolefin resin and a polyvinyl acetal resin (excluding polyvinyl formal resin) containing a plasticizer, and further contains a flexible resin. The present invention was discovered by discovering that when materials containing a large amount of plasticizer, such as interlayer film sheets made of polyvinyl acetal resins such as PVB, are kneaded with a polyolefin resin during recycling, adding the flexible resin makes it possible to control bleeding of the resulting resin composition, thereby achieving an effect of suppressing bleeding of the contained plasticizer.

[0014] The interlayer film sheet often uses an ester compound containing an ether bond in its molecule as a plasticizer because of its good affinity with polyvinyl acetal resins such as PVB. Therefore, in the present invention, the plasticizer is preferably an ester compound containing an ether bond in its molecule. This ester compound has a low environmental impact as an ester, is highly productive, and can be provided inexpensively, so it is often included in materials for interlayer films and the like. This compound also has excellent electrical conductivity and bleeding resistance. Specific examples include diethylene glycol di-2-ethylhexanoate, triethylene glycol di-n-hexanoate, diethylene glycol di-n-hexanoate, triethylene glycol di-2-ethylhexanoate, and bis(2-(2-butoxyethoxy)ethyl) adipate. Particularly preferred esters include triethylene glycol di-2-ethylhexanoate and bis(2-(2-butoxyethoxy)ethyl) adipate. The compound may be used alone or in combination of two or more kinds.

[0015] The flexible resin is at least one resin selected from the group consisting of synthetic rubber, elastomer, and copolymerized olefin resin. The synthetic rubber is preferably at least one selected from the group consisting of ethylene propylene rubber (EPM), ethylene propylene diene rubber (EPDM), butadiene rubber (BR), styrene butadiene rubber (SBR), nitrile rubber (NR), nitrile butadiene rubber (NBR), isoprene rubber, and mixtures thereof. Styrene butadiene / butylene / styrene (SBBS) is preferably used as the elastomer. Furthermore, ethylene vinyl acetate copolymer (EVA) is preferably used as the copolymerized olefin resin. One type of flexible resin may be blended alone, or two or more types of the flexible resins may be blended in combination.

[0016] For example, even when the flexible resin is added in a small amount, such as 2.5 parts by weight, to 60 parts by weight of a polyolefin resin and 20 parts by weight of a polyvinyl acetal resin containing a plasticizer, which is a component equivalent to an interlayer film, the effect of suppressing bleeding of the plasticizer is obtained. In the above, the blending amount of the flexible resin is preferably 5.0 to 30 parts by weight, as this provides a large effect of suppressing bleeding. More preferably, it is in the range of 10 to 20 parts by weight.

[0017] The polyvinyl acetal resin is preferably at least one selected from the group consisting of polyvinyl acetoacetal and polyvinyl butyral. The molecular weight of the polyvinyl acetal resin is preferably 1,000 or more, more preferably 10,000 or more. According to the present invention, the molecular weight of the polyvinyl acetal resin is 1.0×10 5In the present invention, the weight ratio of the content of the polyolefin resin to the content of the polyvinyl acetal resin is preferably in the range of polyolefin resin:polyvinyl acetal resin=99.9:0.1 to 0.1:99.9, and more preferably in the range of polyolefin resin:polyvinyl acetal resin=99.5:0.5 to 50:50, and more preferably in the range of 99:1 to 75:25.

[0018] The polyolefin resin is preferably at least one selected from the group consisting of polypropylene resin, polyethylene resin, and various copolymers containing the above resins as the main component. The polyolefin resin is particularly preferably at least one selected from the group consisting of polypropylene resin and polyethylene resin. Furthermore, the polyolefin resin may be blended singly or two or more polyolefin resins may be blended in combination.

[0019] The resin composition of the present invention may further contain general additives such as inorganic fillers, organic fillers, pigments, dyes, radical initiators, flame retardants, antioxidants, antibacterial agents, bacteriostatic agents, and disinfectants as optional components, provided that the effects of the present invention are not impaired. Examples of suitable radical initiators include peroxidizers. Examples of suitable antioxidants include polyphenols such as catechin.

[0020] The resin composition of the present invention can be produced, for example, by adding each material to a kneader, mixing them, and then extruding them in an extruder. Simply adding the flexible resin as a third component during mixing can control the bleeding characteristics of the resulting resin composition, making it possible to utilize raw resin materials that are prone to bleeding after recycling. If necessary, the resulting resin composition may be pelletized or processed into a sheet or film. In particular, sheets and films have a large surface area, so even a small amount of bleeding can affect the overall product, including its feel and performance. Therefore, they can be preferably used as products to which this technology is applicable. [Example]

[0021] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0022] [Reference example] Figure 6 shows the results of measurements using a typical process waste PVB interlayer film (containing plasticizer) sheet as a test piece. This process waste has a molecular weight of approximately 1.1 × 10 5 The main component was PVB, and it contained approximately 25% ester-based plasticizer (PVB:plasticizer = 3:1). Figure 6 shows the infrared spectrum of the surface of this test piece sheet measured by ATR measurement using a diamond crystal using a Spectrum One made by PerkinElmer Japan Co., Ltd., in order to observe bleeding of this test piece. In the figure, the dashed line shows the infrared spectrum of the surface of this test piece when a pressure of 40% was applied using the pressure unit of the universal ATR attached to the device. The solid line shows the infrared spectrum measured after the above measurement, when the pressure was released and the test piece was removed from the diamond crystal, without wiping off the diamond crystal. 1700cm -1 From 1800cm -1 It can be seen that a peak due to bleeding exists between these two points.

[0023] Hereinafter, as in the above, the test piece was once pressed with 40% force using the ATR pressure unit, and after release, the test piece was removed from the diamond crystal, and the infrared spectrum (hereinafter sometimes referred to as "infrared spectrum for bleeding evaluation") was measured as is without wiping the diamond crystal, and the bleeding performance was evaluated by comparing it with the bleeding amount in this reference example.

[0024] [Comparative Example 1] Figure 7(A) shows the infrared spectrum (infrared spectrum for bleeding evaluation) of a test piece obtained by kneading components corresponding to an interlayer film using low-density polyethylene (LDPE, "Novatec HD" LC525, manufactured by Japan Polyethylene Corporation) as a polyolefin resin and forming it into a sheet using the T-die method. As in the reference example, the test piece was initially pressed at 40% pressure using the ATR pressure unit, and then released. The test piece was then removed from the diamond crystal and measured without wiping off the diamond crystal. The dashed line in the figure shows the infrared spectrum for bleeding evaluation of this test piece. The solid line shows the infrared spectrum for bleeding evaluation of the reference example.

[0025] The molecular weight of the intermediate film equivalent component is 1.15 × 10 5 The PVB ("S-LEC B·K" BH-A, manufactured by Sekisui Chemical Co., Ltd.) was blended with triethylene glycol di-2-ethylhexanoate (G-260, manufactured by Sekisui Chemical Co., Ltd.) as a plasticizer at a weight ratio of PVB:plasticizer = 3:1. 20 parts by weight of the interlayer film equivalent component was added to 60 parts by weight of the polyolefin resin and kneaded, and the mixture was formed into a sheet using the T-die method to obtain a test specimen.

[0026] In Comparative Example 1, in which no flexible resin component was added, the peaks due to bleeding were found to be larger in the infrared spectrum for bleeding evaluation than in the Reference Example. As such, it was confirmed that when the interlayer film sheet material was blended with a polyolefin resin and molded, the plasticizer bleeds (bleeds out), making it difficult to use as a product.

[0027] [Example 1] Figure 1 shows the infrared spectrum (infrared spectrum for bleeding evaluation) measured in the same manner as in the Reference Example for a test piece obtained by kneading an interlayer film component and a flexible resin component and forming them into a sheet using the T-die method, using low-density polyethylene (LDPE, "Novatec HD" LC525, manufactured by Japan Polyethylene Corporation) as the polyolefin resin. The dashed line in the figure shows the infrared spectrum for bleeding evaluation for this test piece. The solid line shows the infrared spectrum for bleeding evaluation for the Reference Example.

[0028] As a component corresponding to the interlayer film, a polymer having a molecular weight of 1.15 × 10 5 The PVB ("S-LEC B·K" BH-A, manufactured by Sekisui Chemical Co., Ltd.) was blended with triethylene glycol di-2-ethylhexanoate (G-260, manufactured by Sekisui Chemical Co., Ltd.) as a plasticizer at a weight ratio of PVB:plasticizer = 3:1. 60 parts by weight of the polyolefin resin was mixed with 20 parts by weight of the component corresponding to the interlayer film and 5 parts by weight of block-type styrene-butadiene rubber B-SBR ("Nipol" NS380S, manufactured by Zeon Corporation) as a flexible resin component, and the mixture was kneaded and formed into a sheet using the T-die method to obtain a test specimen.

[0029] In this example, in which 5 parts by weight of block styrene-butadiene rubber was added as a flexible resin component, the peaks due to bleeding in the infrared spectroscopy spectrum for bleeding evaluation were comparable to those in the Reference Example, indicating that bleeding of the plasticizer due to blending of polyolefin resins was suppressed.

[0030] [Example 2] A test piece was prepared in the same manner as in Example 1, except that 10 parts by weight of block-type styrene-butadiene rubber B-SBR ("Nipol" NS380S, manufactured by Zeon Corporation) was added as the flexible resin component. The results of measuring the infrared spectroscopy spectrum for bleeding evaluation are shown in FIG. 2. In the figure, the broken line indicates the infrared spectroscopy spectrum for bleeding evaluation of this test piece. The solid line indicates the infrared spectroscopy spectrum for bleeding evaluation of a reference example.

[0031] In this example, in which 10 parts by weight of block styrene-butadiene rubber was added as a flexible resin component, peaks due to bleeding were observed in the infrared spectroscopy spectrum for bleeding evaluation, but they were smaller than those in the Reference Example, and it was found that bleeding of the plasticizer due to blending of the polyolefin resin was suppressed.

[0032] [Example 3] A test piece was prepared in the same manner as in Example 1, except that 15 parts by weight of block-type styrene-butadiene rubber B-SBR ("Nipol" NS380S, manufactured by Zeon Corporation) was added as the flexible resin component. The results of measuring the infrared spectroscopy spectrum for bleeding evaluation are shown in FIG. 3. In the figure, the dashed line indicates the infrared spectroscopy spectrum for bleeding evaluation of this test piece. The solid line indicates the infrared spectroscopy spectrum for bleeding evaluation of a reference example.

[0033] In this example, in which 15 parts by weight of block styrene-butadiene rubber was added as a flexible resin component, almost no peaks due to bleeding were observed in the infrared spectroscopy spectrum for bleeding evaluation, and a bleeding control effect superior to that of the Reference Example was obtained, indicating that bleeding of the plasticizer was suppressed even by blending polyolefin resin.

[0034] [Example 4] A test specimen was prepared in the same manner as in Example 1, except that 20 parts by weight of random styrene-butadiene rubber R-SBR ("Nipol" 1502, manufactured by Zeon Corporation) was added as the flexible resin component. The results of measuring the infrared spectroscopy spectrum for bleeding evaluation are shown in FIG. 4. In the figure, the broken line indicates the infrared spectroscopy spectrum for bleeding evaluation of this test specimen. The solid line indicates the infrared spectroscopy spectrum for bleeding evaluation of a reference example.

[0035] In this example, in which 20 parts by weight of random styrene-butadiene rubber was added as a flexible resin component, almost no peaks due to bleeding were observed in the infrared spectroscopy spectrum for bleeding evaluation, and a bleeding control effect superior to that of the Reference Example was obtained, indicating that bleeding of the plasticizer was suppressed even by blending polyolefin resin.

[0036] [Example 5] A test piece was prepared in the same manner as in Example 1, except that 20 parts by weight of ethylene vinyl acetate copolymer EVA (Ultrathene injection grade 633, manufactured by Tosoh Corporation), a copolymerized olefin resin, was added as the flexible resin component. The results of measuring the infrared spectrum for bleeding evaluation are shown in FIG. 5. In the figure, the dashed line indicates the infrared spectrum for bleeding evaluation of this test piece. The solid line indicates the infrared spectrum for bleeding evaluation of a reference example.

[0037] In this example, in which 20 parts by weight of ethylene-vinyl acetate copolymer was added as a flexible resin component, almost no peaks due to bleeding were observed in the infrared spectroscopy spectrum for bleeding evaluation, and a bleeding control effect superior to that of the Reference Example was obtained, indicating that bleeding of the plasticizer was suppressed even by blending polyolefin resins.

[0038] Comparative Example 2 Figure 7(B) shows an infrared spectrum (infrared spectrum for bleeding evaluation) measured in the same manner as the Reference Example for a test piece obtained by kneading and injection molding components corresponding to an interlayer film using low-density polyethylene (LDPE, "Novatec HD" LC525, manufactured by Japan Polyethylene Corporation) as the polyolefin resin. In the figure, the broken line indicates the infrared spectrum for bleeding evaluation for this test piece. The solid line indicates the infrared spectrum for bleeding evaluation for the Reference Example.

[0039] The intermediate film equivalent component is the process waste material (molecular weight: approximately 1.1 × 10 5The main component was PVB, and the content of an ester-based plasticizer was approximately 25% (PVB:plasticizer = 3:1). 20 parts by weight of the component corresponding to the interlayer film was added to 60 parts by weight of the polyolefin resin, and the mixture was kneaded, followed by forming into a sheet by the T-die method to obtain a test specimen.

[0040] In Comparative Example 2, in which no flexible resin component was added, the peaks due to bleeding in the infrared spectrum for bleeding evaluation were found to be larger than in the Reference Example. As such, it was confirmed that when the interlayer film sheet material was blended with a polyolefin resin and molded, the plasticizer bleeds (bleeds out), making it difficult to use as a product.

[0041] [Example 6] Figure 8(A) shows an infrared spectrum (infrared spectrum for bleeding evaluation) measured in the same manner as in the Reference Example for a test piece obtained by kneading a component corresponding to an interlayer film and a flexible resin component and forming the mixture into a sheet using the T-die method, using low-density polyethylene (LDPE, "Novatec HD" LC525, manufactured by Japan Polyethylene Corporation) as the polyolefin resin. In the figure, the broken line indicates the infrared spectrum for bleeding evaluation for this test piece. The solid line indicates the infrared spectrum for bleeding evaluation for the Reference Example.

[0042] As in Comparative Example 2, the intermediate film equivalent component was the process waste material of the Reference Example (molecular weight: approximately 1.1 × 10 5 The main component was PVB, and the content of an ester-based plasticizer was approximately 25% (PVB:plasticizer = 3:1). 20 parts by weight of the component corresponding to the interlayer film and 2.5 parts by weight of block-type styrene-butadiene rubber B-SBR (Nipol NS380S, manufactured by Zeon Corporation) as a flexible resin component were added to 60 parts by weight of the polyolefin resin, and the mixture was kneaded, and the mixture was molded into a sheet using a T-die method to obtain a test specimen.

[0043] In this example, in which 2.5 parts by weight of block styrene-butadiene rubber was added as a flexible resin component, the peak due to bleeding in the infrared spectrum for bleeding evaluation was larger than that of the Reference Example, but smaller than that of Comparative Example 2, in which no flexible resin component was added. Thus, it was found that bleeding of the plasticizer due to blending of the polyolefin resin was suppressed even when only 2.5 parts by weight of block styrene-butadiene rubber was added.

[0044] [Example 7] A test piece was prepared in the same manner as in Example 6, except that 5 parts by weight of block-type styrene-butadiene rubber B-SBR ("Nipol" NS380S, manufactured by Zeon Corporation) was added as the flexible resin component. The results of measuring the infrared spectroscopy spectrum for bleeding evaluation are shown in FIG. 8(B). In the figure, the dashed line indicates the infrared spectroscopy spectrum for bleeding evaluation of this test piece. The solid line indicates the infrared spectroscopy spectrum for bleeding evaluation of the reference example.

[0045] In this example, in which 5 parts by weight of block styrene-butadiene rubber was added as a flexible resin component, peaks due to bleeding were observed in the infrared spectroscopy spectrum for bleeding evaluation, but they were smaller than those in the Reference Example, and it was found that bleeding of the plasticizer due to blending of the polyolefin resin was suppressed.

[0046] [Example 8] A test piece was prepared in the same manner as in Example 6, except that 10 parts by weight of block-type styrene-butadiene rubber B-SBR ("Nipol" NS380S, manufactured by Zeon Corporation) was added as the flexible resin component. The results of measuring the infrared spectroscopy spectrum for bleeding evaluation are shown in FIG. 8(C). In the figure, the dashed line indicates the infrared spectroscopy spectrum for bleeding evaluation of this test piece. The solid line indicates the infrared spectroscopy spectrum for bleeding evaluation of the reference example.

[0047] In this example, in which 10 parts by weight of block styrene-butadiene rubber was added as a flexible resin component, peaks due to bleeding were observed in the infrared spectroscopy spectrum for bleeding evaluation, but they were smaller than those in the Reference Example, and it was found that bleeding of the plasticizer due to blending of the polyolefin resin was suppressed.

[0048] [Example 9] A test piece was prepared in the same manner as in Example 6, except that 15 parts by weight of block-type styrene-butadiene rubber B-SBR ("Nipol" NS380S, manufactured by Zeon Corporation) was added as the flexible resin component. The results of measuring the infrared spectroscopy spectrum for bleeding evaluation are shown in FIG. 8(D). In the figure, the dashed line indicates the infrared spectroscopy spectrum for bleeding evaluation of this test piece. The solid line indicates the infrared spectroscopy spectrum for bleeding evaluation of the reference example.

[0049] In this example, in which 15 parts by weight of block styrene-butadiene rubber was added as a flexible resin component, almost no peaks due to bleeding were observed in the infrared spectroscopy spectrum for bleeding evaluation, and a bleeding control effect superior to that of the Reference Example was obtained, indicating that bleeding of the plasticizer was suppressed even by blending polyolefin resin.

[0050] [Example 10] A test piece was prepared in the same manner as in Example 6, except that 20 parts by weight of block-type styrene-butadiene rubber B-SBR ("Nipol" NS380S, manufactured by Zeon Corporation) was added as the flexible resin component. The results of measuring the infrared spectroscopy spectrum for bleeding evaluation are shown in Figure 8(E). In the figure, the dashed line indicates the infrared spectroscopy spectrum for bleeding evaluation of this test piece. The solid line indicates the infrared spectroscopy spectrum for bleeding evaluation of the reference example.

[0051] In this example, in which 20 parts by weight of block styrene-butadiene rubber was added as a flexible resin component, almost no peaks due to bleeding were observed in the infrared spectroscopy spectrum for bleeding evaluation, and a bleeding control effect superior to that of the Reference Example was obtained, indicating that bleeding of the plasticizer was suppressed even by blending polyolefin resin.

[0052] [Example 11] A test piece was prepared in the same manner as in Example 6, except that 20 parts by weight of a high-diene type ethylene propylene diene rubber (EPDM, "ESPRENE505", manufactured by Sumitomo Chemical Co., Ltd.) was added as the flexible resin component. The results of measuring the infrared spectroscopy spectrum for bleeding evaluation are shown in FIG. 9(A). In the figure, the dashed line indicates the infrared spectroscopy spectrum for bleeding evaluation of this test piece. The solid line indicates the infrared spectroscopy spectrum for bleeding evaluation of a reference example.

[0053] In this example, in which 20 parts by weight of ethylene propylene diene rubber was added as a flexible resin component, the peak due to bleeding in the infrared spectrum for bleeding evaluation was larger than that of the Reference Example, but smaller than that of Comparative Example 2, in which no flexible resin component was added. Thus, it was found that bleeding of the plasticizer due to blending of the polyolefin resin was suppressed even when 20 parts by weight of ethylene propylene diene rubber was added.

[0054] [Example 12] A test piece was prepared in the same manner as in Example 6, except that 20 parts by weight of ethylene vinyl acetate copolymer EVA (Ultrathene injection grade 633, manufactured by Tosoh Corporation), a copolymerized olefin resin, was added as the flexible resin component. The results of measuring the infrared spectrum for bleeding evaluation are shown in Figure 9(B). In the figure, the dashed line indicates the infrared spectrum for bleeding evaluation of this test piece. The solid line indicates the infrared spectrum for bleeding evaluation of a reference example.

[0055] In this example, in which 20 parts by weight of ethylene-vinyl acetate copolymer was added as a flexible resin component, almost no peaks due to bleeding were observed in the infrared spectroscopy spectrum for bleeding evaluation, and a bleeding control effect superior to that of the Reference Example was obtained, indicating that bleeding of the plasticizer was suppressed even by blending polyolefin resins.

[0056] (Method of preparing test specimens) The test pieces used in the above measurements were prepared as follows: When a material was not blended in each test piece, that step was omitted as appropriate, and the following preparation method was applied.

[0057] First, as a preliminary preparation of each material, each material was processed into a shape (for example, powder particles of several millimeters square) that could be put into the hopper of a twin-screw extruder.

[0058] Next, the materials were mixed together before being charged into the hopper of a twin-screw extruder.

[0059] Next, the materials processed as described above were kneaded using a twin-screw extruder equipped with a T-die (T-die). The twin-screw extruder used was a "KZW15-45HG" (Φ = 15, L / D = 45) manufactured by Technovel Co., Ltd. The operating conditions for the device were a screw rotation speed of 250 rpm and a feeder discharge rate of 15 g / min. The twin-screw extruder had six cylinders (1st to 6th), and the set temperatures for the first to sixth cylinders and the T-die were 160°C. The materials were heated and mixed in the twin-screw extruder, and the resin mixture was extruded from the T-die of the twin-screw extruder. The extruded mixture was a sheet, which was immediately cooled and solidified on a rotating cooling roll set at 25°C, then wound onto a paper tube to obtain a test specimen.

[0060] Comparative Example 3 Figure 10(A) shows the results of extracting surface components from a test piece obtained by kneading low-density polyethylene (LDPE, "Novatec HD" LC525, manufactured by Japan Polyethylene Corporation) as a polyolefin resin and forming it into a sheet using a hot press method, and then measuring the extracted components using gas chromatography-mass spectrometry.

[0061] The molecular weight of the intermediate film equivalent component is 1.15 × 10 5 The PVB ("S-LEC B·K" BH-A, manufactured by Sekisui Chemical Co., Ltd.) was blended with triethylene glycol di-2-ethylhexanoate (G-260, manufactured by Sekisui Chemical Co., Ltd.) as a plasticizer at a weight ratio of PVB:plasticizer = 2:1. 20 parts by weight of the components corresponding to the interlayer film were added to 60 parts by weight of the polyolefin resin, and the mixture was batch-mixed, and then sheet-formed by hot pressing to obtain test specimens.

[0062] In Comparative Example 3, in which no flexible resin component was added, the peak area value at the retention time (15.15 min) due to the plasticizer component was 6,651,785, and it can be seen that the peak due to bleeding was large, similar to Comparative Example 1. In this way, it was confirmed that when the interlayer film sheet material is blended with a polyolefin resin and molded, the plasticizer bleeds (bleeds out), making it difficult to use as a product.

[0063] Comparative Example 4 Figure 10(B) shows the results of extracting surface components from a test piece obtained by kneading components equivalent to an interlayer film and forming the resulting sheet using a hot press method, using low-density polyethylene (LDPE, "Novatec HD" LC525, manufactured by Japan Polyethylene Co., Ltd.) as a polyolefin resin. The extracted components were then measured using gas chromatography-mass spectrometry.

[0064] The molecular weight of the intermediate film equivalent component is 1.15 × 10 5The PVB ("S-LEC B·K" BH-A, manufactured by Sekisui Chemical Co., Ltd.) was blended with bis(2-(2-butoxyethoxy)ethyl) adipate (BXA-N, manufactured by Daihachi Chemical Industry Co., Ltd.) as a plasticizer at a weight ratio of PVB:plasticizer = 2:1. 20 parts by weight of the interlayer film equivalent component was added to 60 parts by weight of the polyolefin resin, and the mixture was batch-mixed, and then sheet-formed by hot pressing to obtain test specimens.

[0065] In Comparative Example 4, in which no flexible resin component was added, the peak area value at the retention time (16.71 min) due to the plasticizer component was 4,520,398, and it can be seen that the peak due to bleeding was large, similar to Comparative Example 1. In this way, it was confirmed that when the interlayer film sheet material is blended with a polyolefin resin and molded, the plasticizer bleeds (bleeds out), making it difficult to use as a product.

[0066] [Example 13] Figure 10(C) shows the results of extracting surface components from a test piece obtained by kneading an interlayer film-equivalent component and a flexible resin component, using low-density polyethylene (LDPE, "Novatec HD" LC525, manufactured by Japan Polyethylene Co., Ltd.) as the polyolefin resin, and forming the mixture into a sheet using a hot press method. The extracted components were then measured using gas chromatography-mass spectrometry.

[0067] The molecular weight of the intermediate film equivalent component is 1.15 × 10 5 The PVB (S-LEC B·K BH-A, manufactured by Sekisui Chemical Co., Ltd.) was blended with bis(2-(2-butoxyethoxy)ethyl) adipate (BXA-N, manufactured by Daihachi Chemical Industry Co., Ltd.) as a plasticizer at a weight ratio of PVB:plasticizer = 2:1. 60 parts by weight of the polyolefin resin was mixed with 20 parts by weight of the interlayer film component and 10 parts by weight of ethylene-vinyl acetate copolymer EVA (Ultrathene injection grade 633, manufactured by Tosoh Corporation), a copolymerized olefin resin, as a flexible resin component, and the mixture was batch-mixed and then molded into sheets using a hot press to obtain test specimens.

[0068] In this example, in which 10 parts by weight of ethylene vinyl acetate copolymer was added as a flexible resin component, the peak area value at the retention time (16.71 min) due to the plasticizer component was 1,361,081, which indicates that the amount of plasticizer bleeding was suppressed to approximately 30% compared to Comparative Example 4.

[0069] The test pieces for measurement used in Comparative Examples 3 and 4 and Example 13 were prepared as follows. (batch type kneading) Each material was placed in a batch kneader (10S100, manufactured by Toyo Seiki Seisakusho Co., Ltd.) set at 140°C, and kneaded for 10 minutes at a rotation speed of 12.5 rpm to obtain a kneaded sample.

[0070] (heat press method) Approximately 2.5 g of the kneaded sample obtained above was weighed out and placed in a 10 cm x 10 cm x 0.3 mm spacer, and then heated and pressed using a tabletop press (small press G-12, manufactured by Techno Supply Co., Ltd.) set to 140 ° C., and then immediately sandwiched between metal plates with tap water running through them to cool, thereby obtaining a sheet-like test piece. The thickness of the obtained sheet-like test piece was approximately 0.3 mm.

[0071] (Gas Chromatography Mass Spectrometry) The amount of surface bleeding of the sheet-like test piece was measured using a gas chromatograph mass spectrometer (GCMS QP-2010Ultra, manufactured by Shimadzu Corporation) under the following method and conditions.

[0072] <Method for extracting surface components (bleed)> A 10 mm × 30 mm strip sample was cut from the sheet-like test piece. The strip sample was immersed in 1 mL of ethyl alcohol in a vial at room temperature and shaken for 1 minute. Thereafter, the strip sample was removed from the vial, and the remaining ethyl alcohol solution was used as a sample for gas chromatography-mass spectrometry.

[0073] <Gas chromatographic conditions> Column: A capillary column with a length of 30 m and an inner diameter of 0.25 mm, the inner wall of which is coated with a liquid phase consisting of 5% phenylmethylpolysiloxane with a film thickness of 0.25 μm. Temperature conditions: After holding at 40°C for 2 minutes, increase the temperature to 300°C at 20°C / min and hold at 300°C for 5 minutes Carrier gas: He gas, gas linear velocity 40 cm / sec

[0074] <Mass spectrometry conditions> Equipment: Quadrupole mass spectrometer Ionization method: EI (ionization voltage 70 eV) Scan mass: m / z 33-500

[0075] The above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiments, and the above-described embodiments can be appropriately modified and carried out without departing from the spirit of the present invention. [Industrial Applicability]

[0076] The present invention makes it possible to utilize commercially available polyvinyl acetal for laminated glass interlayer sheets containing a liquid plasticizer. The present invention makes it possible to utilize, as a valuable resource, materials such as used glass interlayers, which have previously been discarded due to difficulties in recycling due to issues with handling and properties. This not only has the effect of reducing the burden on the environment, but is also thought to make a significant contribution to industrial use.

Claims

1. The composition comprises at least one polyolefin resin selected from the group consisting of polypropylene resins and polyethylene resins, and a polyvinyl acetal resin (excluding polyvinyl formal resins) containing a plasticizer including an ester compound having an ether bond in the molecule, The rubber composition further comprises at least one flexible resin selected from the group consisting of synthetic rubber selected from ethylene propylene rubber, ethylene propylene diene rubber, butadiene rubber, styrene butadiene rubber, and isoprene rubber, styrene butadiene / butylene / styrene elastomer, and copolymerized olefin resin; a weight ratio of the content of the polyolefin-based resin to the content of the polyvinyl acetal resin containing the plasticizer (polyolefin-based resin:polyvinyl acetal resin containing the plasticizer) is within a range of 99:1 to 75:25; A resin composition characterized in that the weight ratio of the content of the polyvinyl acetal resin containing the plasticizer to the content of the flexible resin (polyvinyl acetal resin containing the plasticizer:flexible resin) is within a range of 20:2.5 to 20:

30.

2. 2. The resin composition according to claim 1, wherein in the polyvinyl acetal resin containing the plasticizer, a weight ratio of the content of the polyvinyl acetal resin to the content of the plasticizer (polyvinyl acetal resin:plasticizer) is in the range of 3:1 to 2:

1.

3. The resin composition according to claim 1 or 2, wherein the flexible resin contains an ethylene-vinyl acetate copolymer as the copolymerized olefin resin.

4. The resin composition according to claim 1 , wherein the polyvinyl acetal resin is at least one selected from the group consisting of polyvinyl acetoacetal and polyvinyl butyral.

5. A method for recycling a polyvinyl acetal resin (excluding polyvinyl formal resin) containing a plasticizer including an ester compound having an ether bond in the molecule, comprising: when kneading the polyvinyl acetal resin containing a plasticizer with at least one polyolefin-based resin selected from the group consisting of polypropylene resins and polyethylene resins, a weight ratio of the content of the polyolefin-based resin to the content of the polyvinyl acetal resin containing a plasticizer (polyolefin-based resin:polyvinyl acetal resin containing a plasticizer) is set within a range of 99:1 to 75:25, A method for recycling a polyvinyl acetal resin, comprising adding, as a bleed control agent, at least one flexible resin selected from the group consisting of a synthetic rubber selected from ethylene propylene rubber, ethylene propylene diene rubber, butadiene rubber, styrene butadiene rubber, and isoprene rubber, a styrene butadiene / butylene / styrene elastomer, and a copolymerized olefin resin, such that the weight ratio of the content of the polyvinyl acetal resin containing a plasticizer to the content of the flexible resin is in the range of plasticizer-containing polyvinyl acetal resin:flexible resin=20:2.5 to 20:30.

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