Vacuum forming sheet and method for manufacturing vacuum formed member

Abstract

To provide a sheet for vacuum forming capable of satisfactorily exhibiting a reflection suppressing function even after vacuum forming, and a method for manufacturing a vacuum formed member.SOLUTION: The sheet for vacuum forming has a main surface and includes a polyolefin as a main component and a filler dispersed in the polyolefin, and the glossiness of the main surface after vacuum forming is less than 10%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a vacuum forming sheet and a method for manufacturing a vacuum formed member. [Background technology]

[0002] For example, Patent Document 1 below discloses a blow-molded article that is molded from a material containing ABS resin and 1,2-butadiene rubber, characterized in that the amount of the 1,2-butadiene rubber is 0.3 to 15 parts by weight per 100 parts by weight of the ABS resin. The blow-molded article is used, for example, as an exterior part for an automobile. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-196763 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, molded articles (vacuum-formed articles) obtained by vacuum forming are sometimes used as interior materials for automobiles. Here, vehicle interior materials are sometimes subjected to surface roughening treatments such as embossing and graining for the purpose of reducing reflection. Vacuum-formed articles are usually subjected to the surface roughening treatment during the manufacturing process of the molded article. In this case, the roughened state of the molded article may be damaged by vacuum forming, resulting in the occurrence of so-called gloss reversion. This results in a problem of reduced reflection-reducing effects due to the surface roughening treatment.

[0005] An object of one aspect of the present disclosure is to provide a vacuum forming sheet and a method for manufacturing a vacuum formed member that can exhibit good anti-reflection function even after vacuum forming. [Means for solving the problem]

[0006] In some aspects, the present disclosure relates to the following [1] to

[11] , etc. [1] A vacuum forming sheet having a main surface, comprising a polyolefin as a main component and a filler dispersed in the polyolefin, wherein the gloss of the main surface after vacuum forming is less than 10%. [2] The sheet for vacuum forming according to [1], wherein the gloss of the main surface after vacuum forming is less than 8%. [3] The sheet for vacuum forming according to [1] or [2], wherein the gloss of the main surface before vacuum forming is 50% or more. [4] The sheet for vacuum forming according to any one of [1] to [3], wherein the difference in gloss of the main surface before and after vacuum forming is 7.5% or less. [5] The sheet for vacuum forming according to [4], wherein the difference in gloss of the main surface before and after vacuum forming is 2% or less. [6] The sheet for vacuum forming according to any one of [1] to [5], which has a thickness of 1.0 mm or more and 5.0 mm or less, and the filler is talc having a median diameter of 4 μm or more and 20 μm or less. [7] The vacuum forming sheet according to [6], wherein the filler content is 5% by mass or more and 30% by mass or less. [8] A vacuum forming sheet according to any one of [1] to [7], wherein the polyolefin comprises polypropylene and polyethylene, the polyolefin having a content of polypropylene greater than the content of polyethylene, the polyethylene comprising high-density polyethylene and low-density polyethylene, and the polyethylene having a content of high-density polyethylene greater than the content of low-density polyethylene. [9] The vacuum forming sheet according to any one of [1] to [8], which does not contain an elastomer.

[10] The vacuum forming sheet according to any one of [1] to [9], which is a sheet for vehicle interior materials.

[11] A method for manufacturing a vacuum-formed member, comprising: a first step of preparing a sheet having a polyolefin as a main component and a filler dispersed in the polyolefin; and a second step of forming a molded body by vacuum forming the sheet, wherein after the second step, the gloss of the main surface of the molded body is less than 10%. [Effects of the Invention]

[0007] According to one aspect of the present disclosure, it is possible to provide a vacuum forming sheet and a method for manufacturing a vacuum formed member that can exhibit good anti-reflection function even after vacuum forming. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1(a) is a perspective view showing a sheet member according to an embodiment, and FIG. 1(b) is a schematic cross-sectional view of a portion of the sheet member according to an embodiment. [Figure 2] FIG. 2(a) is a perspective view showing an example of a molded body that is a sheet member after vacuum molding, and FIG. 2(b) is a schematic cross-sectional view of a main part of the molded body shown in FIG. 2(a). [Figure 3] 3(a) and 3(b) are diagrams illustrating an example of a method for manufacturing a sheet member according to an embodiment. [Figure 4] 4(a) and 4(b) are diagrams illustrating an example of a method for producing a molded body. [Figure 5] 5(a) and 5(b) are diagrams illustrating an example of a method for producing a molded body. [Figure 6] FIG. 6 is a perspective view showing a sheet member according to a modified example. [Figure 7] FIG. 7 is a diagram for explaining an example of a method for manufacturing a sheet member according to a modified example. [Figure 8] FIG. 8(a) is a photograph showing the sheet member of Example 1 before vacuum forming, and FIG. 8(b) is a photograph showing the sheet member of Example 1 after vacuum forming. [Figure 9]FIG. 9(a) is a photograph showing the sheet member of Example 2 before vacuum forming, and FIG. 9(b) is a photograph showing the sheet member of Example 2 after vacuum forming. [Figure 10] FIG. 10(a) is a photograph showing the sheet member of Comparative Example 1 before vacuum forming, and FIG. 10(b) is a photograph showing the sheet member of Comparative Example 1 after vacuum forming. [Figure 11] FIG. 11(a) is a photograph showing the sheet member of Comparative Example 2 before vacuum forming, and FIG. 11(b) is a photograph showing the sheet member of Comparative Example 2 after vacuum forming. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a preferred embodiment of one aspect of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same elements or elements having the same functions will be denoted by the same reference numerals, and redundant description will be omitted.

[0010] (vacuum forming sheet) FIG. 1(a) is a perspective view showing a sheet member according to this embodiment, and FIG. 1(b) is a schematic cross-sectional view of a portion of the sheet member according to this embodiment. As shown in FIGS. 1(a) and 1(b), the sheet member 1 is a sheet-like member (vacuum forming sheet) that can be stretched and deformed into a desired shape by vacuum forming, and is used, for example, as a material for covers, housings, exterior materials, interior materials, etc. In one example, the sheet member 1 is used as a material for vehicle interior materials (vehicle interior material sheet) or vehicle exterior materials (vehicle exterior material sheet). The thickness of the sheet member 1 is not particularly limited, but is, for example, 1.0 mm or more and 5.0 mm or less. In this case, the vacuum forming of the sheet member 1 can effectively perform a surface roughening treatment (described in detail below).

[0011] The sheet member 1 has a main surface 1a. The main surface 1a is the portion of the sheet member 1 that will become the surface of the vacuum-formed product (vacuum-formed member). In this embodiment, the main surface 1a of the sheet member 1 before vacuum forming is a flat surface. In this specification, a surface with a glossiness of 50% or more is considered to be a flat surface. In this embodiment, the glossiness of the main surface 1a before vacuum forming is 50% or more, 60% or more, or 70% or more. The surface glossiness is measured according to the method defined in JIS Z 8741:1997. In measuring the glossiness, the angle of incidence and the angle of reception are set to 60°, but are not limited to this.

[0012] The sheet member 1 is a molded product of the raw material described below. In one example, the sheet member 1 is a member formed by extrusion molding the raw material. In one example, the flexural modulus, Charpy impact value, and melt tension of the sheet member 1 satisfy the values ​​described below. The specific gravity of the sheet member 1 at room temperature (e.g., 23°C) is, for example, 0.93 or more and 1.05 or less. The upper limit of the specific gravity may be 1.02, 1.00, or 0.98. The specific gravity of the sheet member 1 is measured, for example, according to the method defined in JIS K 7112:1999 or ISO 1183:1987. The specific gravity of the sheet member 1 at room temperature is the same as or substantially the same as the specific gravity of the raw material.

[0013] FIG. 2(a) is a perspective view showing an example of a molded body, which is a sheet member after vacuum forming. As shown in FIG. 2(a), the molded body 2 is a member (vacuum-formed sheet member, vacuum-formed member) obtained by vacuum forming at least a portion of the sheet member 1, and is used, for example, as a cover, housing, exterior material, interior material, etc. The molded body 2 may be, for example, a vehicle exterior material such as a spoiler or bumper, or a vehicle interior material such as a dashboard. The molded body 2 may be attached to a three-dimensional object, such as an automobile part. In this case, the shape of the molded body 2 may conform to the shape of the three-dimensional object. Although not shown, the molded body 2 may include a non-formed portion that is not deformed by vacuum forming. In one example, the non-formed portion remains after vacuum forming a portion of the sheet member 1. If the non-formed portion remains in the molded body 2, the non-formed portion may be used as a portion to which an adhesive is applied, for example. Alternatively, the entire sheet member 1 may be vacuum-formed so that the non-formed portion does not remain, or the non-formed portion may be excluded from the molded body 2. In this specification, when the non-formed portion remains, the main surface of the non-formed portion is not included in the main surface 2 a of the formed body 2 .

[0014] FIG. 2(b) is a schematic cross-sectional view of a main portion of the molded body shown in FIG. 2(a). The molded body 2 is a vacuum-formed portion of the sheet member 1, and has a main surface 2a. The main surface 2a corresponds to the main surface 1a after vacuum forming. As shown in FIG. 2(b), the main surface 2a is rougher than the main surface 1a shown in FIG. 1(b). In this embodiment, the main surface 1a becomes the main surface 2a by vacuum forming the sheet member 1. In other words, in this embodiment, the molded body 2 is roughened without undergoing a roughening treatment different from vacuum forming. Therefore, in this embodiment, the vacuum forming of the sheet member 1 can add a reflection suppressing function to the molded body 2, for example.

[0015] In this embodiment, the main surface 2a is not flat but is a rough surface. Therefore, as shown in FIG. 2(b), the main surface 2a has minute irregularities. The irregularities may be uniform or non-uniform. In this specification, a surface having a glossiness of less than 10% is considered to be a rough surface. In this embodiment, the glossiness of the main surface 2a (i.e., the main surface 1a of the sheet member 1 after vacuum forming) is less than 10%, less than 8%, 7.8% or less, or 7.5% or less. In this embodiment, the difference between the glossiness of the main surface 1a and the glossiness of the main surface 2a (i.e., the difference in glossiness of the main surface before and after vacuum forming) is 40% or more, 50% or more, or 60% or more.

[0016] (Raw material for sheet member 1) The raw materials of the sheet member 1 include polyolefin as a main component and filler dispersed in the polyolefin. Therefore, it can be said that the sheet member 1 comprises polyolefin as a main component and filler dispersed in the polyolefin. The polyolefin and filler will be described in detail below.

[0017] (A) Polyolefin Polyolefin is an organic compound that is the main component of the sheet member 1. For example, the polyolefin content is 80% by mass or more and 95% by mass or less, based on the total amount of raw materials. For example, the polyolefin includes polypropylene and polyethylene. In this case, the polypropylene content in the polyolefin is greater than the polyethylene content. The melt flow rate (MFR) of the polyolefin is, for example, less than 5 g / 10 min. For example, the MFR of polyolefins is measured according to the method defined in JIS K7210-1:2014, under conditions of a measurement temperature of 230°C and a load of 2.16 kg. The lower the MFR of the polyolefin, the more suitable the raw material containing the polyolefin is for extrusion molding and vacuum molding rather than injection molding. Known measuring instruments are used to measure the MFR. The MFR of the polyolefin may be 3 g / 10 min or less, 1 g / 10 min or less, 0.8 g / 10 min or less, or 0.5 g / 10 min or less. When polyolefins are extrusion molded and / or vacuum molded, the MFR of the polyolefins is preferably 1 g / 10 min or less, more preferably 0.8 g / 10 min or less, and even more preferably 0.5 g / 10 min or less. The MFR of polyolefins and the like is measured, for example, using a melt indexer (L203) manufactured by Takara Kogyo Co., Ltd.

[0018] Polypropylene is a polymer that is the main component of polyolefins. Polypropylene as the main component of polyolefins provides excellent impact resistance and allows for the production of relatively inexpensive raw materials. When the polypropylene content is 50% by mass or more based on the total amount of polyolefins, polypropylene corresponds to the main component of the polyolefin. For example, the polypropylene content is 50% by mass or more and 90% by mass or less based on the total amount of polyolefins. The content may be 60% by mass or more, or 70% by mass or more. The content may be 85% by mass or less, 80% by mass or less, or 75% by mass or less. When the polypropylene content is within the above range, higher impact resistance and other properties are obtained compared to when the polyolefin is polypropylene alone. The MFR of polypropylene is, for example, less than 5 g / 10 min. The MFR of polypropylene may be 3 g / 10 min or less, 1 g / 10 min or less, 0.8 g / 10 min or less, or 0.5 g / 10 min or less.

[0019] Polypropylene is a polymer of propylene, but is not limited to this. In one example, polypropylene also includes copolymers with other monomers. That is, polypropylene is not limited to homopolypropylene, but may also include ethylene-propylene block copolymers (block polypropylenes), ethylene-propylene random copolymers (random polypropylenes), and copolymers of propylene with α-olefins other than ethylene and propylene (propylene-based copolymers). Examples of α-olefins include 1-butene, 1-pentene, isobutylene, 3-methyl-1-butene, 1-hexene, 3,4-dimethyl-1-butene, 1-heptene, and 3-methyl-1-hexene.

[0020] The polypropylene may be acid-modified polypropylene. Acid-modified polypropylene is polypropylene into which an acidic group has been introduced. For example, polypropylene obtained by copolymerizing or graft-polymerizing maleic anhydride, carboxylic acid, sulfonic acid, or a derivative thereof with polypropylene may correspond to acid-modified polypropylene.

[0021] In one example, the polypropylene includes at least one of the above-mentioned homopolypropylene, block polypropylene, random polypropylene, propylene-based copolymer, and acid-modified polypropylene. The polypropylene may also include, for example, multiple different propylene-based copolymers.

[0022] Polyethylene is a polymer that is a secondary component of polyolefin. The inclusion of polyethylene in polyolefin can improve the impact resistance, rigidity, low-temperature resistance, and breaking strength of the sheet member 1. When the polyethylene content is less than 50% by mass, based on the total amount of polyolefin, polyethylene corresponds to a secondary component of polyolefin. For example, the polyethylene content is 20% by mass or more and less than 50% by mass, based on the total amount of polyolefin. The content may be 30% by mass or more, or 35% by mass or more. The content may also be 45% by mass or less, 40% by mass or less, or 42% by mass or less. When the polyethylene content is within the above range, the impact resistance and other properties of a molded article primarily composed of the polyolefin are improved. The MFR of the polyethylene is, for example, less than 5 g / 10 min. The MFR of the polyethylene may be 3 g / 10 min or less, 1 g / 10 min or less, 0.8 g / 10 min or less, or 0.5 g / 10 min or less.

[0023] The polyethylene includes at least one of high-density polyethylene (HDPE) and low-density polyethylene (LDPE). When the polyethylene content is less than 50% by mass, based on the total amount of polyethylene, the polyethylene corresponds to a minor component of the polyolefin. In this embodiment, the polyethylene includes both HDPE and LDPE. In this case, the HDPE content in the polyethylene is greater than the LDPE content. In one example, based on the total amount of polyethylene, the HDPE content is 60% by mass or more and 90% by mass or less. The content may be 70% by mass or more, or 75% by mass or more. The content may also be 85% by mass or less, 80% by mass or less, or 77.5% by mass or less. In other words, based on the total amount of polyethylene, the LDPE content is 10% by mass or more and 40% by mass or less. Furthermore, based on the total amount of polyolefin, the HDPE content is 30% by mass or more and 48% by mass or less. The content may be 35% by mass or more, or 37.5% by mass or more. The content may be 45% by mass or less, 42.5% by mass or less, or 40% by mass or less. In other words, the LDPE content is 2% by mass or more and 20% by mass or less, based on the total amount of polyolefin. When the HDPE content is within the above range, the impact resistance and other properties of a molded article primarily composed of polyolefin are improved.

[0024] High-density polyethylene (HDPE) is polyethylene defined by, for example, JIS K 6922-1:2018. The density of high-density polyethylene is, for example, 0.942 g / cm 3 The MFR of the high-density polyethylene is, for example, less than 5 g / 10 min. The MFR of the high-density polyethylene may be 3 g / 10 min or less, 1 g / 10 min or less, 0.8 g / 10 min or less, 0.5 g / 10 min or less, or 0.3 g / 10 min or less.

[0025] High-density polyethylene is a polymer of ethylene, but is not limited to this. In one example, high-density polyethylene also includes copolymers with other monomers. That is, high-density polyethylene according to one example is not limited to homopolyethylene, but also includes copolymers of ethylene and an α-olefin such as 1-butene (ethylene-based copolymers).

[0026] Low-density polyethylene (LDPE) is polyethylene defined by, for example, JIS K 6922-1:2018. The density of low-density polyethylene is, for example, 0.911 g / cm 3 Greater than 0.911g / cm 3 The density of low-density polyethylene is, for example, 0.901 g / cm3, but is not limited to this. 3 The low-density polyethylene may be, for example, less than 5 g / 10 min. The MFR of the low-density polyethylene may be 3 g / 10 min or less, 1 g / 10 min or less, 0.8 g / 10 min or less, 0.5 g / 10 min or less, or 0.3 g / 10 min or less.

[0027] Low-density polyethylene is a polymer of ethylene, but is not limited to this. In one example, low-density polyethylene also includes copolymers with other monomers. That is, low-density polyethylene according to one example is not limited to homopolyethylene, but also includes copolymers of ethylene with α-olefins such as 1-butene, 1-hexene, and 1-octene (ethylene-based copolymers).

[0028] The polyethylene may be modified polyethylene, which is polyethylene into which a functional group has been introduced.

[0029] For example, the MFR of each of polypropylene, high-density polyethylene, and low-density polyethylene is preferably 1 g / 10 min or less, more preferably 0.8 g / 10 min or less, and even more preferably 0.5 g / 10 min or less. From the viewpoint of the kneadability of the polyolefin, it is preferable that the MFR of the high-density polyethylene and the MFR of the low-density polyethylene are each approximately the same as the MFR of polypropylene.

[0030] (B) Filler The filler is a powdery filling material dispersed in polyolefin. Examples of the filler include inorganic materials such as glass fiber, silica, calcium carbonate, clay, talc, mica, titanium oxide, and carbon black. From the perspective of surface roughening treatment by vacuum molding, the filler may be talc having a median diameter of 4 μm to 20 μm. In this case, the unevenness caused by the filler can be effectively formed on the main surface 2a of the molded body 2 by vacuum molding.

[0031] For example, the filler content is 5% by mass or more and 30% by mass or less, based on the total amount of raw materials. The content may be 8% by mass or more, 10% by mass or more, or 15% by mass or more. The content may be 25% by mass or less, 20% by mass or less, 18% by mass or less, or 15% by mass or less. The content corresponds to the filler content in the sheet member 1. The MFR of the filler is, for example, less than 1 g / 10 min. The MFR of the filler may be 0.8 g / 10 min or less, 0.5 g / 10 min or less, 0.3 g / 10 min or less, or 0.1 g / 10 min or less.

[0032] From the viewpoint of dispersibility in polyolefin, the filler may have the inorganic material and a coating material that coats the inorganic material. The coating material is, for example, a polyolefin such as polyethylene or polypropylene. The coating material may be polypropylene or low-density polyethylene. Based on the total amount of the filler, the content of the coating material is, for example, 10% by mass or more and 40% by mass or less. The content may be 20% by mass or more, or 25% by mass or more. Furthermore, the content may be 35% by mass or less, or 30% by mass or less. When the filler contains a coating material, the content of the coating material is also taken into consideration when determining the content of the polyolefin in the raw material.

[0033] The raw material containing (A) and (B) is produced by a known method, such as melt-kneading. The raw material may contain additives in addition to (A) and (B). Alternatively, the raw material may be produced without adding additives. The additives may include, for example, plasticizers, tackifiers, dyes, pigments, antioxidants, antistatic agents, adhesives, antiblocking agents, slip agents, heat stabilizers, light stabilizers, foaming agents, colorants, etc.

[0034] In one example, the MFR of the raw material is, for example, less than 5 g / 10 min. The MFR of the raw material may be 3 g / 10 min or less, 1 g / 10 min or less, 0.8 g / 10 min or less, or 0.5 g / 10 min or less. When the resin composition is extrusion molded and / or vacuum molded, the MFR of the resin composition is preferably 1 g / 10 min or less, more preferably 0.8 g / 10 min or less, and even more preferably 0.5 g / 10 min or less. The MFR of a resin composition for injection molding is generally at least 5 g / 10 min or more, and preferably 10 g / 10 min or more.

[0035] In this embodiment, the raw materials do not include ABS resin (acrylonitrile, butadiene, styrene copolymer synthetic resin). Therefore, the sheet member 1 also does not include ABS resin. Since the raw materials do not include ABS resin, the specific gravity of the raw materials can be made smaller than that of ABS resin, and the sheet member 1 can be made lighter. In this embodiment, the raw materials do not include elastomer. Therefore, the sheet member 1 also does not include elastomer.

[0036] (Physical properties of sheet member 1) For example, the flexural modulus of the sheet member 1 at room temperature is, for example, 1200 MPa or more. The flexural modulus of the sheet member 1 at room temperature may be 1400 MPa or more, 1500 MPa or more, or 1600 MPa or more. From the viewpoint of the manufacturing cost of the sheet member 1, the flexural modulus of the sheet member 1 at room temperature is, for example, 2500 MPa or less, 2200 MPa or less, 2000 MPa or less, 1900 MPa or less, or 1850 MPa or less. The flexural modulus of the sheet member 1 is measured according to the method defined in JIS K 7171:2016 or ISO 178:2010.

[0037] The flexural modulus of the sheet member 1 corresponds to the flexural modulus of a sample formed from the raw material or a sample obtained by processing the sheet member 1. In the former case, the sample may be formed from the raw material using the same method as the sheet member 1. In the latter case, the sheet member 1 may be cold-worked to prevent changes in the performance of the sheet member 1. For example, a part cut from the sheet member 1 corresponds to the sample. The part may be polished or otherwise processed. On the other hand, the flexural modulus of a structure formed to a desired dimension by melting the sheet member 1 does not correspond to the flexural modulus of the sheet member 1. The same applies to the Charpy impact value, deflection temperature under load, high-speed impact resistance, and high-speed cold impact resistance described below. When the method specified in JIS K 7171:2016 is used to measure the flexural modulus, a sample having dimensions of long sides: 60 mm, short sides: 25 mm, and thickness: 3 mm may be used. For example, an autograph (AGS-5KNA) manufactured by Shimadzu Corporation may be used to measure the flexural modulus. In addition, when measuring the properties of the sheet member 1 described below, such as the Charpy impact value, deflection temperature under load, high-speed impact resistance, and high-speed cold impact resistance, samples prepared by any of the methods described above are used.

[0038] For example, the Charpy impact value of the sheet member 1 at room temperature is 35 kJ / m 2 The Charpy impact value of the sheet member 1 at room temperature is 35 kJ / m 2 As a result, the sheet member 1 can have higher impact resistance than conventional molded articles made of ABS-based resin compositions. At room temperature, the Charpy impact value of the sheet member 1 is 40 kJ / m 2 It can be more than 50kJ / m 2 It can be more than 60kJ / m 2 From the viewpoint of the manufacturing cost of the sheet member 1, the Charpy impact value of the sheet member 1 at room temperature is set to, for example, 100 kJ / m 2 Below, 90J / m 2 Below, 80kJ / m 2 or less than 70kJ / m 2The ABS resin composition is a resin composition containing ABS resin as the main component.

[0039] In one example, the Charpy impact value of the sheet member 1 at low temperature is 5 kJ / m 2 At low temperatures, the Charpy impact value of the sheet member 1 is 15 kJ / m 2 It can be more than 20kJ / m 2 It can be more than 25kJ / m 2 It can be more than 30kJ / m 2 From the viewpoint of the manufacturing cost of the sheet member 1, the Charpy impact value of the sheet member 1 at low temperatures may be, for example, 65 kJ / m 2 Below, 50kJ / m 2 Below, 40kJ / m 2 Below, 35kJ / m 2 or less than 30kJ / m 2 The following is the result.

[0040] The Charpy impact value of the sheet member 1 is measured according to the method specified in JIS K 7111-1:2012, both at room temperature and at low temperatures. The Charpy impact value of the sheet member 1, both at room temperature and at low temperatures, corresponds to the Charpy impact value of a sample formed from the raw material described above, or the Charpy impact value of a sample processed from the sheet member 1. When the method specified in JIS K 7111-1:2012 is used to measure the Charpy impact value, a sample having dimensions of long side: 80 mm, short side: 10 mm, and thickness: 3 mm may be used. The Charpy impact value may be measured using, for example, an impact testing machine (DG-UB) manufactured by Toyo Seiki Seisakusho, Ltd.

[0041] For example, the melt tension of the sheet member 1 at 190°C is 45 mN or more. When the melt tension is 45 mN or more, the sheet member 1 can be successfully manufactured by vacuum forming. The higher the melt tension of the sheet member 1, the less likely thickness unevenness occurs in the sheet member 1 after processing. Note that the lower the melt flow rate of the raw material, the higher the melt tension of the sheet member 1 tends to be.

[0042] The melt tension of the sheet member 1 at 190°C corresponds to the melt tension of a sample formed from the above-mentioned raw materials or the melt tension of a sample obtained by processing the sheet member 1. The melt tension of the sheet member 1 is measured, for example, according to the following method. In one example, the sheet member 1 is first pulverized. Then, the pulverized material is melted in a heating furnace included in a Capilograph (manufactured by Toyo Seiki Seisaku-sho, Ltd.). At this time, the heating furnace is set to 190°C. Next, a filamentous resin extruded from an orifice (orifice diameter: 1.0 mm, orifice length: 10.0 mm) attached to the heating furnace is taken up by a take-up device via a pulley. The take-up device takes up the filamentous resin at a speed of 1.57 m / min. The magnitude of the tension applied to the pulley when the take-up device takes up the filamentous resin is defined as the melt tension of the sheet member 1.

[0043] An example of a method for manufacturing a molded body 2 (vacuum molded member) according to this embodiment will be described below with reference to Figures 3(a) and (b), 4(a) and (b), and 5(a) and (b). First, an example of a method for manufacturing a sheet member 1, which is part of the method for manufacturing a molded body 2 according to this embodiment, will be described below with reference to Figures 3(a) and (b). Note that Figures 3(a) and (b) are each diagrams for explaining an example of a method for manufacturing a sheet member 1 according to this embodiment, and Figures 4(a) and (b) and 5(a) and (b) are each diagrams for explaining an example of a method for manufacturing a molded body.

[0044] The raw materials are processed into a sheet member 1 by extrusion molding. In one example, as shown in FIG. 3(a), an extrusion molding apparatus 100 is used to prepare a sheet member comprising a polyolefin as a main component and a filler dispersed in the polyolefin (first step). In the first step, raw material R is first charged into a hopper 101 of the extrusion molding apparatus 100. At this time, raw material R itself may be charged, or (A) and (B) may be charged separately or simultaneously. Raw material R, (A), etc. may be solid or liquid. Next, raw material R is heated and melted in a cylinder 102, and the raw materials are kneaded by a screw 103. Next, a kneaded material 110 is extruded from the cylinder 102 through a die 104 to the outside of the extrusion molding apparatus 100. Next, as shown in FIG. 3(b), the kneaded material 110 is cooled by flat rolls 106 to 108 included in a cooling section 105 and formed into a sheet. Then, the sheet-like kneaded material 110 is cut by a cutter 109, whereby the sheet member 1 is manufactured.

[0045] Next, the sheet member 1 is vacuum-formed to form a molded body 2 (second step). In the second step, first, as shown in FIG. 4(a), the sheet member 1 is placed in a heating device 200. At this time, the sheet member 1 is maintained in a state of being pulled horizontally by clampers 201 and 202 of the heating device 200. Next, the sheet member 1 is heated by heaters 203 and 204. For example, the sheet member 1 is heated to a temperature of 150°C or higher and 250°C or lower. This softens the sheet member 1, for example, as shown in FIG. 4(b).

[0046] Next, as shown in FIG. 5(a), a mold 301 of a vacuum forming device 300 is pressed against the heated sheet member 1. This causes the sheet member 1 to elongate and deform. Here, air is sucked out between the mold 301 and the sheet member 1, so that at least a portion of the sheet member 1 elongates and deforms into a shape that conforms to the surface of the mold 301. By carrying out the vacuum forming described above, a molded body 2 is produced, as shown in FIG. 5(b). Note that the main surface 1a of the sheet member 1 is not pressed against the mold 301.

[0047] As shown in FIG. 5(a), the main surface 2a of the molded body 2 is roughened by vacuum molding. The main surface 1a is roughened by forming irregularities on the surface of the stretched and deformed portion of the sheet member 1 due to the filler present in the sheet member 1. Therefore, in the second step, the stretched and deformed portion of the main surface 1a of the sheet member 1 is roughened, and a rough main surface 2a is formed. Therefore, according to the above-described manufacturing method, the gloss of the main surface 2a of the molded body 2 can be set to less than 10% without performing a roughening treatment before or after the second step.

[0048] The glossiness of the main surface 2a of the molded body 2 obtained by vacuum forming the sheet member 1 produced by the manufacturing method described above is less than 10%. Therefore, by vacuum forming the sheet member 1, it is possible to provide the molded body 2 that can exhibit good anti-reflection function.

[0049] In one example, the gloss of the main surface 2a after vacuum forming may be less than 8%, which makes it possible to provide a molded body 2 that can more effectively exhibit its anti-reflection function.

[0050] In one example, the glossiness of the main surface before vacuum forming may be 50% or more. Even in this case, it is possible to provide a molded body 2 that can exhibit a good anti-reflection function.

[0051] For example, the sheet member 1 may have a thickness of 1.0 mm or more and 5.0 mm or less, and the filler may be talc having a median diameter of 4 μm or more and 20 μm or less. In this case, the unevenness caused by the filler can be well formed on the main surface 2a of the molded body 2 by vacuum molding.

[0052] In one example, the filler content is 5% by mass or more and 30% by mass or less, in which case the unevenness caused by the filler can be formed well at the intended locations by vacuum forming.

[0053] In one example, the polyolefin may include polypropylene and polyethylene, and the polyolefin may contain a larger amount of polypropylene than the polyethylene, and the polyethylene may include a high-density polyethylene and a low-density polyethylene, and the polyethylene may contain a larger amount of high-density polyethylene than the low-density polyethylene. In this case, the flexural modulus and melt tension of the molded body 2 can be improved.

[0054] In one example, the sheet member 1 does not contain an elastomer. This allows the surface of the portion of the sheet member 1 that is stretched and deformed by vacuum forming to easily deform to conform to the shape of the filler. Therefore, the unevenness caused by the filler can be effectively formed on the main surface 2a of the molded body 2 by vacuum forming.

[0055] In one example, the sheet member 1 may be a sheet for vehicle interior materials. In this case, a vehicle interior material with improved texture can be provided without performing a special surface roughening treatment after vacuum forming.

[0056] Next, a sheet member according to a modified example will be described with reference to Fig. 6. In the following, descriptions of parts that overlap with the above embodiment will be omitted.

[0057] FIG. 6 is a perspective view showing a sheet member according to a modified example. As shown in FIG. 6, the main surface 5a of the sheet member 5 according to the modified example has an uneven surface. The main surface 5a may be a rough surface. That is, the glossiness of the main surface 5a may be less than 10%. Alternatively, the main surface 5a may not be a flat surface. In this modified example, the main surface 5a is formed during the manufacturing of the sheet member 5, but this is not limited to this. The main surface 5a may also be formed by a roughening treatment performed after the manufacturing of the sheet member 5. The sheet member 5 is vacuum formed using the same method as in the above embodiment. This produces a molded body (not shown). The main surface of the molded body is a rough surface, as in the above embodiment. That is, the glossiness of the main surface of the molded body is less than 10%. In this modified example, the difference between the glossiness of the main surface 5a and the glossiness of the main surface of the molded body (i.e., the difference in glossiness of the main surface before and after vacuum forming) is, for example, 7.5% or less. In this case, the user of the sheet member 5 can easily estimate the reflectance of the main surface of the molded body, etc. The difference may be 5% or less, 3% or less, or 2% or less.

[0058] Next, an example of a manufacturing method for a sheet member 5 according to a modified example will be described with reference to FIG. 7. FIG. 7 is a diagram for explaining an example of a manufacturing method for a sheet member 5 according to a modified example. As shown in FIG. 7, a kneaded material 110 is extruded to the outside of an extrusion molding apparatus (not shown). Subsequently, as shown in FIG. 3(b), the kneaded material 110 is cooled and formed into a sheet by flat rolls 106 and 108 and a graining roll 107A included in a cooling section 105A. Here, one side of the sheet-shaped kneaded material 110 is roughened by the graining roll 107A. As a result, one side of the sheet-shaped kneaded material 110A that has passed through the cooling section 105A becomes rough or is no longer flat. Then, the kneaded material 110A is cut by a cutter 109, thereby manufacturing the sheet member 5.

[0059] The glossiness of the main surface of the molded body obtained by vacuum molding the sheet member 5 according to the modified example described above is less than 10%. In other words, by using the sheet member 5 according to the modified example, the gloss reversion (flattening of the main surface) that accompanies vacuum molding is unlikely to occur. Therefore, this modified example can also achieve the same effects as the above embodiment.

[0060] The vacuum forming sheet and the method for manufacturing a vacuum formed member according to one aspect of the present disclosure are not limited to the above-described embodiment and modified examples. For example, in the above-described embodiment and modified examples, the sheet member has a single-layer structure, but is not limited to this. The sheet member may have a multi-layer structure. In this case, for example, a sheet member having a multi-layer structure may be manufactured using a co-extrusion device. [Example]

[0061] The present disclosure will be explained in more detail by the following examples, but the present disclosure is not limited to these examples.

[0062] Example 1 First, a mixture of 50% by mass of polypropylene (manufactured by SunAllomer Co., Ltd., model number: VB170A), 35% by mass of high-density polyethylene (manufactured by Keiyo Polyethylene Co., Ltd., model number: T4002), 5% by mass of low-density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., model number: F102-0), and 10% by mass of filler (manufactured by Sanfuku Kogyo Co., Ltd., talc masterbatch, model number: MFP-TP20) was prepared as raw materials. The mixture was extruded using an extruder (GM50-36V) manufactured by GM Engineering Co., Ltd. The mixture discharged from the extruder was then formed into a sheet using multiple flat rolls. This resulted in the formation of the sheet member 10 (thickness: 3.0 mm) shown in FIG. 8(a).

[0063] Next, a portion of the heated sheet member 10 was stretched and deformed using a vacuum forming device (manufactured by Fuse Vacuum Co., Ltd., model number: BVF-0710-PWB). As a result, a formed body 11 was formed in a portion of the sheet member 10, as shown in FIG. 8(b). Therefore, in FIG. 8(b), both the formed body 11 and the non-formed body 12 are present. As shown in FIG. 8(b), a gloss was visible in the non-formed body 12, but no gloss was visible in the formed body 11. The processing conditions for the sheet member 10 using the vacuum forming device were a forming temperature of 170°C, a vacuuming time of 20 seconds, and a cooling time of 100 seconds.

[0064] Example 2 A sheet member 20 (thickness: 3.0 mm) shown in FIG. 9(a) was formed under the same conditions as in Example 1, except that the mixture discharged from the extruder was formed into a sheet using a plurality of flat rolls and a grain roll. Then, under the same conditions as in Example 1, a formed body 21 was formed in a part of the sheet member 20, as shown in FIG. 9(b). Therefore, in FIG. 9(b), both the formed body 21 and the non-formed body 22 are present. As shown in FIG. 9(b), no gloss was visually observed in either the formed body 21 or the non-formed body 22.

[0065] (Comparative Example 1) A sheet member 30 (thickness: 3.0 mm) shown in FIG. 10(a) was formed under the same conditions as in Example 1, except that a mixture of 50% by mass of polypropylene (manufactured by SunAllomer Co., Ltd., model number: VB170A), 10% by mass of polyethylene (manufactured by Keiyo Polyethylene Co., Ltd., model number: T4002), 8% by mass of elastomer (styrene-based block copolymer) (manufactured by Kraton Polymer Japan Co., Ltd., model number: G1657), and 22% by mass of inorganic filler (manufactured by Takehara Chemical Industry Co., Ltd., model number: MAX1470T) was prepared as the raw materials. Then, under the same conditions as in Example 1, a molded body 31 was formed on a portion of the sheet member 30, as shown in FIG. 10(b). Therefore, both the molded body 31 and the non-molded body 32 are present in FIG. 10(b). As shown in FIG. 10(b), gloss was visually observed in both the molded body 31 and the non-molded body 32.

[0066] (Comparative Example 2) A sheet member 40 (thickness: 3.0 mm) shown in FIG. 11(a) was formed under the same conditions as in Comparative Example 1, except that the mixture discharged from the extruder was formed into a sheet using a plurality of flat rolls and a grain roll. Then, under the same conditions as in Comparative Example 1, a formed body 41 was formed in a portion of the sheet member 40, as shown in FIG. 11(b). Therefore, in FIG. 11(b), both the formed body 41 and the non-formed body 42 are present. As shown in FIG. 11(b), no gloss was visible in the non-formed body 42, but gloss was visible in the formed body 41.

[0067] (Glossiness of main surface) The glossiness of the main surface of the sheet member and the main surface of the molded article were measured in each of Examples 1 and 2 and Comparative Examples 1 and 2. The glossiness was measured using a Gloss Checker IG-320 (manufactured by Horiba, Ltd.) as a measuring instrument and an LED (wavelength: 880 nm) as a light source. The incident angle and receiving angle were set to 60°.

[0068] In Example 1, the glossiness of the main surface 10a of the sheet member 10 was 71.5%, while the glossiness of the main surface 11a of the molded body 11 was 7.8%. From the above, it can be said that in Example 1, a matte finish was produced by vacuum molding.

[0069] In Example 2, the gloss level of the main surface 20a of the sheet member 20 was 6.5%, and the gloss level of the main surface 21a of the molded body 21 was 7.5%. From the above, it can be said that in Example 2, there was substantially no reversion of gloss due to vacuum molding.

[0070] In Comparative Example 1, the glossiness of the main surface 30a of the sheet member 30 was 85.2%, and the glossiness of the main surface 31a of the molded body 31 was 79.4%. From the above, it can be said that in Comparative Example 1, no matting due to vacuum molding occurred.

[0071] In Comparative Example 2, the gloss level of the main surface 40a of the sheet member 40 was 4.8%, while the gloss level of the main surface 41a of the molded body 41 was 12.4%. From the above, it can be said that in Comparative Example 2, gloss reversion occurred due to vacuum molding. [Explanation of symbols]

[0072] 1, 5, 10, 20, 30, 40...sheet member (vacuum forming sheet), 1a, 10a, 20a, 30a, 40a...main surface, 2, 11, 21, 31, 41...molded body, 2a, 11a, 21a, 31a, 41a...main surface, 12, 22, 32, 42...non-molded body.

Claims

1. A vacuum forming sheet having a main surface, The composition comprises a polyolefin as a main component and a filler dispersed in the polyolefin, The gloss of the main surface after vacuum forming is less than 10%. Sheet for vacuum forming.

2. The vacuum forming sheet according to claim 1 , wherein the gloss of the main surface after vacuum forming is less than 8%.

3. 3. The sheet for vacuum forming according to claim 1, wherein the gloss of the main surface before vacuum forming is 50% or more.

4. 3. The sheet for vacuum forming according to claim 1, wherein the difference in gloss of the main surface before and after vacuum forming is 7.5% or less.

5. The sheet for vacuum forming according to claim 4, wherein the difference in gloss of the main surface before and after vacuum forming is 2% or less.

6. A thickness of 1.0 mm or more and 5.0 mm or less, 3. The vacuum forming sheet according to claim 1, wherein the filler is talc having a median diameter of 4 μm or more and 20 μm or less.

7. The vacuum forming sheet according to claim 6 , wherein the filler content is 5% by mass or more and 30% by mass or less.

8. The polyolefins include polypropylene and polyethylene; In the polyolefin, the content of the polypropylene is greater than the content of the polyethylene, The polyethylene includes high density polyethylene and low density polyethylene, 3. The vacuum forming sheet according to claim 1, wherein the content of the high-density polyethylene in the polyethylene is greater than the content of the low-density polyethylene.

9. The vacuum forming sheet according to claim 1 or 2, which does not contain an elastomer.

10. 3. The vacuum forming sheet according to claim 1, which is a sheet for vehicle interior materials.

11. A first step of preparing a sheet comprising a polyolefin as a main component and a filler dispersed in the polyolefin; a second step of vacuum-forming the sheet to form a molded body; After the second step, the gloss of the main surface of the molded body is less than 10%. A method for manufacturing vacuum formed parts.

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