JP2004161009A - Polyolefinic-resin foam sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foam sheet, a little in change with time and excellent in light resistance and durability, that shows the same texture and the like as in using a usual polyvinyl chloride resin and polyurethane resin, in a polyolefinic-resin foam sheet using a polyolefin resin. <P>SOLUTION: A base resin is obtained by adding a polyolefinic rubber of 50-300 pts.wt. to a polyolefinic resin of 100 pts.wt. having a hardness of ≤60 by a JIS A hardness meter. At least any one layer of a base cloth layer and a surface layer is laminated on the polyolefinic resin foam sheet with expansion ratio of 3-15 using the base resin to give an olefinic resin foam sheet. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to a foamed sheet made of an olefin resin used for stationery, various cases, packaging, furniture, and the like, and more particularly to a flexible olefin resin foam sheet.

  BACKGROUND ART Conventionally, foam sheets and laminates made of various synthetic resins have been used for stationery, various cases, packaging, furniture, and the like. Conventionally, foam sheets and laminates made of polyvinyl chloride resin or polyurethane resin have been mainly used. These sheets are used as artificial leather by giving a three-dimensional design by giving an uneven pattern on the surface or giving a printed pattern or the like to the surface.

  However, when a polyvinyl chloride resin is used, there is a problem that the contained plasticizer is stained to cause yellowing or stickiness, and there is a problem that the cold resistance and oil resistance are poor. Further, since a large amount of plasticizer is used, there is a problem that the surface of the sheet is easily stained, and it is difficult to remove the stain.

  In addition, when polyurethane resin is used, there is no problem such as stains of the plasticizer, but when used for a long time, or when used under conditions of high temperature and humidity, the hydrolysis reaction proceeds, and it is easily brittle. , There was a problem in durability.

  Therefore, the applications of such foamed sheets and laminates are further expanded, and there is a need for those having unprecedented physical properties and characteristics.

  Therefore, a foam sheet and a laminate made of an olefin resin have been attracting attention. As the olefin resin to be used, polyethylene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer and the like are used.

JP-A-09-165462

  However, foam sheets and laminates made of the above-mentioned olefin-based resin are harder to feel in terms of touch, etc., and therefore, compared to those using conventional polyvinyl chloride resin or polyurethane resin. Therefore, the texture was inferior and the use was restricted.

  In addition, because the foamed sheet is hard, when the surface is processed with an uneven pattern, the unevenness is difficult to enter, the processing time is long and the workability is poor, and the obtained uneven pattern is also polyvinyl chloride resin or polyurethane. It was inferior to the case where the resin was used.

  The present invention has been made in order to solve the above-mentioned problems, and in a polyolefin-based resin foam sheet using a polyolefin resin, the texture is equivalent to using a conventional polyvinyl chloride resin or polyurethane resin, An object of the present invention is to provide a foam sheet which has little change over time and is excellent in light resistance and durability.

  The polyolefin-based resin foam sheet of the present invention made to solve the above-mentioned problem is based on a base obtained by adding 50 to 300 parts by weight of a polyolefin-based rubber of 60 or less by a JIS A hardness meter to 100 parts by weight of a polyolefin-based resin. A material resin is used, and at least one of a base fabric layer and a skin layer is laminated on a polyolefin resin foam sheet having an expansion ratio of 3 to 15 times. As for the timing of lamination, even after forming a foamed sheet, the sheet may be laminated in the state of a foamable sheet before foaming and then foamed.

  As the polyolefin resin of the present invention, a copolymer resin is preferable because of good flexibility and good foaming property, and more preferably, ethylene-vinyl acetate copolymer resin and ethylene- (meth) acrylate copolymer are preferable. It is desirable to use at least one of a coalescing resin and an ethylene-high alpha olefin copolymer resin.

  As the ethylene-vinyl acetate copolymer resin, those having a vinyl acetate component of 5 to 30% by weight, particularly those of 15 to 30% by weight in consideration of the foamability and texture (softness) of the obtained foam sheet are preferable. It is. If it exceeds 30% by weight, the heat deformability tends to increase, and it is not preferable in terms of cost.

  Of course, the ethylene-vinyl acetate copolymer resin may be a mixture of resins having different vinyl acetate contents. Further, as long as the properties of the obtained foam sheet are not impaired, a copolymer of monomer components other than ethylene and vinyl acetate may be used.

  Examples of the ethylene- (meth) acrylate copolymer resin include ethylene-methyl methacrylate copolymer resin, ethylene-methyl acrylate copolymer resin, ethylene-ethyl acrylate copolymer resin, and the like. Preferably, the (meth) acrylic acid ester component has a content of 5 to 30% by weight, and particularly preferably has a content of 15 to 30% by weight in consideration of foamability and texture (softness) of the obtained foam sheet. is there. If it exceeds 30% by weight, the heat deformability tends to increase, and it is not preferable in terms of cost.

  Of course, the ethylene- (meth) acrylate copolymer resin may be a mixture of different types of (meth) acrylate and its content, etc., copolymerized with ethylene.

  In addition, as long as the properties of the obtained foam sheet are not impaired, a copolymer of monomer components other than ethylene and (meth) acrylate may be used.

  Examples of the ethylene-high-alpha-olefin copolymer resin include, for example, ethylene-hexene copolymer resin, ethylene-octene copolymer resin, and the like. 30% by weight, particularly 15 to 30% by weight, is preferred in view of the foamability and texture (softness) of the resulting foam sheet. If it exceeds 30% by weight, the heat deformability tends to increase, and it is not preferable in terms of cost.

  Of course, the ethylene-high alpha olefin copolymer resin may be a mixture of different types and contents of the high alpha olefin resin copolymerized with ethylene, and may have a carbon number of less than 6. Even if it is contained, it suffices that the content of 6 or more is 5 to 30% by weight.

  Further, as long as the properties of the obtained foam sheet are not impaired, a copolymer of monomer components other than ethylene and the high alpha olefin resin may be used.

  One or more polyolefin resins selected from the group consisting of ethylene-vinyl acetate copolymer resin, ethylene- (meth) acrylate copolymer resin, and ethylene-high alpha olefin copolymer resin that form a foam sheet are classified into JIS A An olefin rubber having a hardness of 60 or less as measured by a hardness meter is added. If the hardness exceeds 60, it becomes difficult to obtain a soft foam sheet having a good texture. As the olefin rubber, ethylene-propylene rubber, ethylene-butene rubber, propylene-ethylene rubber, propylene-butene rubber and the like can be used. The addition amount is preferably 50 to 300 parts by weight based on 100 parts by weight of the polyolefin copolymer resin. If the amount is less than 50 parts by weight, it is difficult to obtain a soft foam sheet having a good texture, and if it exceeds 300 parts by weight, it is not preferable in terms of workability and quality characteristics.

  A foaming agent is added to foam the base resin obtained by adding the polyolefin rubber to the polyolefin resin. As the blowing agent used, one selected from pyrolytic chemical blowing agents such as azodicarbonamide, oxybisbenzenesulfonyl hydrazide, benzenesulfonyl hydrazide, P-toluenesulfonyl hydrazide, diazoaminobenzene, and azobisisobutyronitrile. Alternatively, two or more kinds can be used in combination.

The amount of the foaming agent to be added is appropriately selected depending on the expansion ratio of the desired foam sheet. For example, when the expansion ratio is about 3 to 15 times, it is about 2 to 20 parts by weight per 100 parts by weight of the base resin.
If necessary, various additives such as an antistatic agent, an antioxidant, a light stabilizer such as a hindered amine compound, a lubricant, an ultraviolet absorber, an inorganic filler, and a coloring agent such as a pigment may be added.

  What is necessary is just to mix | blend a polyolefin resin, a polyolefin rubber, a foaming agent, and a desired additive, and knead it by well-known each means. For example, a method using a pressure kneader, a roll, a Banbury mixer, a static mixer, a screw type extruder, or the like can be used. In some cases, the components that have been dry-blended in advance may be kneaded.

  After kneading, a foamable sheet having a desired thickness is obtained by a calendar roll, a knife coating method or the like. For example, the temperature of the calender roll at this time is desirably 100 to 150 ° C. at which the foaming agent does not foam.

  The obtained foamable sheet is heated to obtain the polyolefin resin foam sheet of the present invention. The heating temperature must be equal to or higher than the thermal decomposition temperature of the foaming agent, and is usually about 160 to 220 ° C.

  Further, if desired, one or both of a skin layer and a base fabric layer are laminated and bonded to each surface of the foamable sheet to form a two-layer or three-layer structure, and then heated to form a foam. Thus, the laminated polyolefin resin foam sheet of the present invention is obtained. By providing the skin layer and the base fabric layer, it is possible to improve the physical properties and the like of the foam sheet of the present invention, and it is possible to expand the usable applications.

  Usually, a non-foamed synthetic resin layer is used as the skin layer. The laminated polyolefin resin foam sheet of the present invention is desirably a skin layer of an olefin resin, and may be the same resin composition as the foamable sheet but without the foaming agent. The same olefin-based resin as the foam sheet is preferable in terms of physical properties such as durability, and can be easily disposed in disposal treatment.

  The formation of the skin layer may be performed by a usual synthetic resin sheet preparation method, similarly to the foamable sheet described above.

  As the base fabric layer, various materials such as woven fabric, knitted fabric, and nonwoven fabric used for ordinary synthetic resin leather and synthetic leather can be used. For example, woven fabrics such as cotton, rayon, polyester, and polyamide can be used. And knitted fabrics, and various nonwoven fabrics such as synthetic resin fibers such as polyethylene, polypropylene and polyester.

  The method of laminating the foam sheet with the skin layer and the base fabric layer is not particularly limited as long as it is a commonly practiced method, and is appropriately selected in consideration of the properties of the foam sheet and the skin layer and the base fabric layer. Is done. For example, when laminating a foam sheet and a skin layer, lamination can be performed through a heating roll or the like. If necessary, an adhesive layer or a primer layer may be provided between the two layers to improve the adhesive strength between the layers. For example, ethylene-vinyl ester copolymer resin, vinyl acetate A hot-melt type or a reactive type such as a resin type or a urethane resin type can be used.

  Further, as for the bonding time, the foamable sheet may be heated and foamed, and even after the foamed sheet of the present invention is formed, the foamed sheet may be laminated in the state of the foamable sheet before foaming and then foamed. In the case where the skin layer or the base fabric layer to be used is not heat-resistant, it is preferable to bond them after foaming because the possibility of impairing the properties of the skin layer and the base fabric layer is reduced.

  Furthermore, after a foamable sheet layer is provided directly on the skin layer or the base fabric layer by a knife coating method or the like, a skin layer or a base fabric layer is attached to the foamable sheet layer surface as necessary to form a three-layer structure. Alternatively, foaming may be performed thereafter. Of course, a three-layer structure may be used after foaming.

As described in detail above, the polyolefin-based resin foam sheet of the present invention, a polyolefin-based resin foam sheet having a skin layer or a base fabric layer, and a polyolefin-based resin foam sheet having a skin layer and a base fabric layer are conventional olefins. It has a better texture than the foamed resin sheet. Also, as compared with a polyvinyl chloride or polyurethane foam sheet, it has the same performance in terms of texture, and is excellent in other durability and the like.

  Hereinafter, the present invention will be described based on specific examples, but the present invention is not limited to the examples described below.

  The composition for an expandable sheet having the composition shown in Table 1 was kneaded with a Banbury mixer.

* Ultracene 634 (Tosoh Corporation): ethylene-vinyl acetate copolymer resin * Acryft WH-202 (Sumitomo Chemical Co., Ltd.): ethylene-methyl methacrylate copolymer resin * Engage 8100 (Dupont Dow Elastomer) ethylene -Octene copolymer resin * Tuffmer (manufactured by Mitsui Chemicals, Inc.): Three types of olefin rubbers having JIS A hardnesses of 41, 55 and 65 are used. The foamed sheets of the present invention were prepared as follows, and each was evaluated as foamed sheets 1 to 10.
(Manufacturing method 1)
Each composition in Table 1 was mixed with a Banbury mixer to form a foamable sheet having a thickness of 0.5 mm and a width of 820 mm using a calender roll at 120 ° C, and this sheet was heated in an oven heated to 190 ° C. The mixture was passed through for 2 minutes to obtain a foam sheet having a thickness of 1.5 mm.

The foamed sheet 10 did not show any improvement in texture due to the amount of the olefin-based rubber added.
(Manufacturing method 2)
Formulations 11 to 13 in Table 3 below were mixed using a Banbury mixer, and a calender roll at 120 ° C. was used to prepare a sheet having a thickness of 0.2 mm and a width of 820 mm. After heat lamination to the conductive sheet, each sheet was passed through an oven heated to 190 ° C. for 2 minutes to obtain a foam sheet having a 1.7 mm-thick skin layer. The foam sheet having each skin layer had a good feeling.

(Production method 3)
Formulation 1 was prepared in the same manner as in Production Method 1, a foamable sheet having a thickness of 0.3 mm × width 820 mm was prepared, and a knitted fabric having a width of 910 mm was bonded thereto. Then, a sheet having a thickness of 0.1 mm and a width of 820 mm was prepared, and this sheet was calender-topped on the side other than the side where the Melias cloth of the foam sheet was bonded to form a foamable sheet having a skin layer and a base cloth layer. The sheet was passed through an oven heated to 190 ° C. for 2 minutes to obtain a 1.2 mm thick foamed leather having a skin layer and a base fabric layer.

  This foamed leather had a better texture than conventional olefin-based leather.

Claims (2)

A polyolefin resin foam having a foaming ratio of 3 to 15 times using a base resin obtained by adding 50 to 300 parts by weight of a polyolefin rubber having a JIS A hardness of 60 or less to 100 parts by weight of the polyolefin resin. A polyolefin resin foam sheet, wherein at least one of a base fabric layer and a skin layer is laminated on the sheet. The polyolefin resin is at least one of an ethylene-vinyl acetate copolymer resin, an ethylene- (meth) acrylate copolymer resin, and an ethylene-high alpha olefin copolymer resin. 2. The polyolefin resin foam sheet according to 1.