JP2012111179A - Embossing roll for extrusion molding and method for producing ethylene copolymer resin sheet using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an embossing roll for extrusion molding capable of preventing rubber catching and deterioration of productivity, and excellent in embossing processability even in molding of an ethylene copolymer resin sheet containing an additive, and a method for producing the ethylene copolymer resin sheet using the same.SOLUTION: The embossing roll for extrusion molding of the ethylene copolymer resin sheet is formed by sequentially laminating a silicone rubber layer, an adhesive layer, and a fluororesin layer on an outer periphery of a shaft core part. Arithmetic mean roughness (Ra) is 5.0 μm or more, and maximum height roughness (Rz) is 25-40 μm. Rubber hardness of the silicone rubber measured by a type A durometer stipulated by JIS K 6253 is preferably 30-80.

Description

The present invention relates to an embossing roll for extrusion molding of an ethylene copolymer resin sheet, and in particular, without forming a rubber even when molding an ethylene copolymer resin sheet containing an additive, The present invention relates to an embossing-type roll for extrusion, which is excellent in productivity and embossability.
The present invention also relates to a method for producing an ethylene copolymer resin sheet using such an embossing roll for extrusion molding.

In extrusion molding, the resin composition is generally melt-kneaded with an extruder, the molten resin is extruded from a die, and formed into a sheet while rapidly cooling with a pair of rolls. As the “one pair of rolls”, a combination of a cooling roll and a pressing roll for pressing a molten resin sheet against the cooling roll is well known.
Further, depending on the use, function and other purposes of the extruded sheet, the molten resin sheet is often cooled and pressed and simultaneously embossed. This embossing is achieved by applying various ideas such as engraving a design on the surface of the pressing roll (hereinafter, the embossing is referred to as an “embossed roll”). To tell).

As an embossing type roll, a layer (single layer or multiple layers) made of rubber or other materials is usually provided on the outer periphery of a metal shaft core portion depending on the use, function and other purposes of the extruded sheet. .
For example, when a rubber roll provided with a rubber layer is employed as an embossed roll, the adhesive strength of the molten resin sheet is greatly different between that for a metal cooling roll and that for a rubber roll. There was a problem that it was easy to adhere to a rubber roll (embossed roll) and the production efficiency deteriorated. In order to solve this problem, a material in which the surface material of the embossed roll is a fluororesin has been proposed (see Patent Document 1).

  On the other hand, although it is not an embossing type roll, a mirror surface forming roll in which a rubber coating layer, an adhesive layer and a fluororesin coating layer are laminated on the outer periphery of the shaft core has also been proposed (see Patent Document 2). As the layer, a rubber material having a Shore B rubber hardness of 60 to 90 is preferable, and it is described that silicone rubber or the like is preferably used from the viewpoint of obtaining excellent heat resistance.

Japanese Utility Model Laid-Open No. 5-16270 Japanese Patent Laid-Open No. 10-249915

In recent years, it has been studied to add a wide variety of additives to the resin in order to impart functionality to the extruded sheet.
Some of these additives cause problems such as bleeding on the sheet surface during molding (processing), vapor due to heat during processing, and adhesion to the lip of the die, which deteriorates the processing suitability. May occur. In particular, the above-mentioned problem appears remarkably when it is a liquid additive. Among the molding apparatuses (processing equipment), rubber rolls are particularly susceptible to the effects of such problems. In the rubber roll, certain additives easily adhere to the surface due to its composition, and the additive may penetrate into the rubber roll. When such a phenomenon occurs, a phenomenon (hereinafter referred to as “rubber”) that the molten resin (sheet) coming out from the die during sheet molding sticks to the rubber roll is likely to occur.
When the rubber breakage occurs, the molten resin is wound around the rubber roll, and it is necessary to stop and clean the apparatus (that is, production), thereby reducing the productivity and making the rubber roll itself unusable.

In consideration of the above points, the present invention does not generate rubber even when molding an ethylene-based copolymer resin sheet containing an additive, does not reduce productivity, and improves embossability. It is an object of the present invention to provide an excellent embossing roll for extrusion molding and a method for producing an ethylene copolymer resin sheet using the same.
On the other hand, the above-mentioned patent document 1 does not describe any details of the resin type of the molten resin sheet, the specific shape of the unevenness, and other forms.
The mirror surface forming roll described in Patent Document 2 has a structure in which a silicone rubber, an adhesive layer, and a fluororesin layer are sequentially laminated, but a plastic sheet that is a mirror-like smooth surface is used. In order to form, it is only a “mirror surface”, and there is no description about a non-uniform uneven shape which is the opposite form. In addition, although it is described that the embossing roll is engraved with a pattern for shaping the lens shape on the metal surface, the configuration and composition thereof, the specific shape of the embossing and other details of the form are described. It has not been.

  As a result of intensive studies in order to solve the above problems, the inventor has a specific laminated structure, that is, the second layer and the third layer on the outer periphery of the shaft core portion, and each of these layers is If it is an embossed roll with specific composition and physical properties, even if it is an ethylene-based copolymer resin blended with various additives, rubber is not taken off during molding, and productivity does not decrease, and it is excellent It was found that embossability can be maintained.

The present invention has been achieved under such knowledge, and is characterized by the following configurations.
(1) An embossing roll for extrusion molding of an ethylene copolymer resin sheet,
A silicone rubber layer, an adhesive layer, and a fluororesin layer are sequentially laminated on the outer periphery of the shaft core, and the arithmetic average roughness (Ra) is 5.0 μm or more, and the maximum height roughness (Rz) is 25. An embossing roll for extrusion molding, which is ˜40 μm.
(2) The embossing roll for extrusion molding according to (1), wherein the silicone rubber has a rubber hardness according to JIS K 6253 durometer type A of 30 to 80.
(3) The embossing roll for extrusion molding according to (1) or (2), wherein the thickness of the fluororesin layer is 0.3 to 0.7 mm.

(4) A method for producing an ethylene copolymer resin sheet using the embossing roll for extrusion molding according to any one of (1) to (3),
The method for producing an ethylene-based copolymer resin sheet, wherein an additive is added in an amount of 1 to 30 parts by weight with respect to 100 parts by weight of the ethylene-based copolymer resin.

The embossing roll for extrusion molding according to the present invention does not generate rubber even when molding an ethylene-based copolymer resin containing various additives, does not reduce productivity, and embossability, etc. Is good.
In addition, according to the method for producing an ethylene copolymer resin sheet of the present invention, an embossing roll for extrusion that exhibits the excellent effects as described above is used, so that a higher quality sheet is produced with a high yield. be able to.

It is explanatory drawing which showed the embossing type | mold roll for extrusion molding of this invention, (A) is a perspective view, (B) is sectional drawing.

The embossing type roll for extrusion molding of the present invention is an embossing type roll for extrusion molding of an ethylene copolymer resin sheet, and a silicone rubber layer, an adhesive layer and a fluororesin layer are sequentially laminated on the outer periphery of a shaft core part. And the arithmetic average roughness (Ra) measured in accordance with JIS B 0601-2001 (conforming to ISO 4287-1997) is 5.0 μm or more, and the maximum height roughness (Rz) is 25 to 40 μm. It is characterized by being.
When the arithmetic average roughness (Ra) is 5.0 μm or more and the maximum height roughness (Rz) is 25 to 40 μm, even if it is an ethylene copolymer resin blended with various additives, It is less likely to be taken off, the embossing is better, and the appearance of the molded sheet is good.
When the arithmetic average roughness (Ra) is less than 5.0 μm, the effect of preventing rubber removal is insufficient. The upper limit of the arithmetic average roughness (Ra) is not particularly limited, and is appropriately set according to a desired surface design (embossed type). For example, when the obtained ethylene-based copolymer resin sheet is used as a sealing material for solar cells, it is suitable that the upper limit is about 10 μm.
When the maximum height roughness (Rz) is less than 25 μm, rubber breakage tends to occur. If it exceeds 40 μm, the appearance of the sheet after molding tends to deteriorate.

In FIG. 1, the embossing type | mold roll 10 for extrusion molding of this invention is shown. FIG. 1A is a perspective view of the embossed roll 10, and FIG. 1B is a cross-sectional view of the roll 10.
As shown in FIG. 1, the embossing roll 10 for extrusion molding according to the present invention is formed by sequentially laminating a silicone rubber layer 3, an adhesive layer (not shown) and a fluororesin layer 4 on the outer periphery of a shaft core portion 2.

<Shaft core>
As the shaft core portion 2, a known shaft core such as an iron core can be used without any limitation within a range not departing from the gist of the present invention.

<Silicone rubber layer>
The rubber hardness of the silicone rubber layer 3 is preferably 30 to 80 according to JIS K 6253 durometer type A (Shore A). If the rubber hardness is less than 30, the difference in hardness between the silicone rubber layer 3 and the fluororesin layer 4 becomes large, and there is a risk of peeling at the interface with the fluororesin layer 4. On the other hand, if the rubber hardness exceeds 80, the rubber becomes too hard and embossing may be difficult. The rubber hardness is more preferably 40 to 70.
The thickness of the silicone rubber layer 3 may be about 0.5 to 5.0 mm from the viewpoint of cooling efficiency.

<Adhesive layer>
The adhesive layer (not shown) is a layer for adhering the silicone rubber layer 3 and the fluororesin layer 4, and a coupling agent, a silicone compound, or other known materials can be used.

<Fluorine resin layer>
Examples of the fluororesin forming the fluororesin layer 4 include fully fluorinated resins such as polytetrafluoroethylene (tetrafluorinated resin, PTFE), polychlorotrifluoroethylene (trifluorinated resin, PCTFE), and polyvinylidene fluoride (PVDF). , And partially fluorinated resins such as polyvinyl fluoride (PVF), perfluoroalkoxy fluororesin (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), ethylene / tetrafluoroethylene copolymer (ETFE) ) And fluorinated resin copolymers such as ethylene / chlorotrifluoroethylene copolymer (ECTFE) can be used.
Among these fluororesins, PFA and / or FEP can be suitably used from the viewpoint of a peeling name with respect to the molten ethylene copolymer resin. These are available as “Teflon (registered trademark)” manufactured by DuPont and “Fullon (registered trademark)” manufactured by Asahi Glass.

The thickness of the fluororesin layer 4 is preferably 0.3 to 0.7 mm, more preferably 0.35 to 0.5 mm.
When the thickness of the fluororesin layer 4 is less than 0.3 mm, when the surface design (embossed type) is formed using sand blasting, the blasted sand may be buried in the silicone rubber layer 3, and the surface design (Embossed type) may be difficult to attach. On the other hand, if it exceeds 0.7 mm, the cooling effect is lowered, and the appearance of the molded sheet may be deteriorated.

<Embossed type>
As described above, the embossing mold is not particularly limited as long as the arithmetic average roughness (Ra) is 5.0 μm or more and the maximum height roughness (Rz) is 25 to 40 μm. It is preferable that the embossing type is not regular or consistent in the depth, height, and distribution (dispersed state) of the unevenness, that is, non-uniform.

The transfer rate of the embossed roll to the sheet is not particularly limited, but is 25 to 50% in relation to the configuration and composition of the embossed roll used in the present invention and the ethylene copolymer resin sheet to be molded. Is preferred.
In addition, about the cooling roll which makes an embossing-type roll and "one set of roll pair", a well-known metal roll and other cooling rolls can be used without a restriction | limiting within the range which does not deviate from the main point of this invention.

  The method for producing an ethylene-based copolymer resin sheet of the present invention uses an embossing roll for extrusion as described above. In the present invention, the embossing roll for extrusion molding as described above is used. Therefore, even if it is a liquid additive that is generally difficult to adapt to various additives and resins, the blending amount thereof is an ethylene copolymer resin. Even if 1 to 30 parts by weight is added to 100 parts by weight, molding can be performed without generating rubber.

Examples of the ethylene copolymer used in the present invention include a copolymer of ethylene and other olefin, a copolymer of olefin and polar monomer, or a mixture thereof. Specific examples of components to be copolymerized include propylene, butene-1, hexene-1, octene-1, 4-methylpentene-1, and higher α-olefins, vinyl esters such as vinyl acetate and vinyl propionate, Α, β- such as methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, n-butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate Examples include α, β-unsaturated carboxylic acids such as unsaturated carboxylic acid alkyl esters, acrylic acid, methacrylic acid, fumaric acid, maleic acid, maleic anhydride, and salts thereof.
In addition, the ethylene copolymer may be a crosslinkable ethylene copolymer capable of forming a crosslinked structure because heat resistance, light resistance, and weather resistance can be further increased.

  Examples of the crosslinkable ethylene copolymer include ethylene-vinyl acetate copolymer or ethylene-α, β unsaturated carboxylic acid alkyl ester copolymer, and ethylene-α, β unsaturated carboxylic acid that can be cross-linked in the presence of metal ions. Examples thereof include an acid copolymer and an ethylene-α, β-unsaturated carboxylic acid-α, β-unsaturated carboxylic acid alkyl ester copolymer.

  Additives to be blended in such an ethylene copolymer resin include organic peroxides and other crosslinking agents, crosslinking aids and coupling agents, and light resistance imparting agents such as HALS (hindered amine light absorber) ( Light stabilizer), UVA (ultraviolet absorber), AO (antioxidant) and other weathering agents.

Any known crosslinking agent can be used without limitation, but an organic peroxide is preferred.
Examples of the organic peroxide include tertiary butyl peroxyisopropyl carbonate, tertiary butyl peroxyacetate, tertiary butyl peroxybenzoate, dicumyl peroxide, 2,5-dimethyl-2,5-bis ( Tert-butylperoxy) hexane, di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexyne-3, 1,1-bis (tert-butylperoxy)- 3,3,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane, methyl ethyl ketone peroxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, tert-butyl hydroperoxide, p-menthane hydroperoxide, benzoyl peroxide, p-chloroben Peroxide, tert-butylperoxy isobutyrate, hydroxyheptyl peroxide, and the like can be used chlorine hexanone peroxide.

  As the crosslinking assistant, trifunctional crosslinking assistants such as triallyl isocyanurate; triallyl isocyanate, and monofunctional crosslinking assistants such as NK ester can be used.

  As the coupling agent, a silane coupling agent is preferable, for example, γ-chloropropyltrimethoxysilane; vinyltrichlorosilane; vinyltriethoxysilane; vinyl-tris- (β-methoxyethoxy) silane; γ-methacryloxypropyltri Methoxysilane; β- (3,4-ethoxycyclohexyl) ethyltrimethoxysilane; γ-glycidoxypropyltrimethoxysilane; vinyltriacetoxysilane; γ-mercaptopropyltrimethoxysilane; γ-aminopropyltrimethoxysilane; N -Β- (aminoethyl) -γ-aminopropyltrimethoxysilane or the like can be used.

  Examples of the light fastness imparting agent (light stabilizer) include 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-. Benzophenones such as carboxybenzophenone and 2-hydroxy-4-n-octoxybenzophenone, 2- (2'-hydroxy-3 ', 5'-ditert-butylphenyl) benzotriazole, 2- (2'- Salicylic acid esters such as benzotriazoles such as hydroxy-5-methylphenyl) benzotriazole and 2- (2'-hydroxy-5-tert-octylphenyl) benzotriazole, phenylsalicylate, p-octylphenylsalicylate Systems, nickel complex salts, hindered amines and the like are used.

  Examples of ultraviolet absorbers and antioxidants include hindered phenols, phosphites, allophanates such as allophanate and methyl allophanate, biurets such as biuret, dimethylbiuret and tetramethylbiuret, L-ascorbic acid and its salts Or an oxide of lanthanide can be used.

  In the present invention, an embossing roll for extrusion molding having good releasability while maintaining processability as described above is used, so that a liquid additive (organic organic solvent) generally considered to be incompatible with an ethylene copolymer resin. Even if an oxide, a crosslinking aid, a silane coupling agent, and the like) are blended, a rubber is not formed and an ethylene copolymer resin sheet that is excellent in embossability can be obtained.

Examples 1-7, Comparative Examples 1-3
The raw material sheet in a molten state obtained by extruding an ethylene copolymer resin composition having the following composition from a T-die extruder is sandwiched between a cooling roll and an embossed roll having the configuration described below, and the transfer rate shown in Table 1 ( %), An ethylene copolymer resin sheet having a thickness of 450 μm was produced.

<Ethylene copolymer resin composition formulation>
・ Ethylene-vinyl acetate copolymer resin (vinyl acetate content 28%, MFR = 18 (Kg / 10 min)): 100 parts by weight ・ Crosslinking agent (trade name “Lupelox 331” manufactured by NOF Corporation): 2 weights Part / crosslinking aid (triallyl isocyanate manufactured by Nippon Kasei Co., Ltd.): 2 parts by weight / silane coupling agent (trade name “KBM503” manufactured by Shin-Etsu Chemical Co., Ltd.): 0.3 part by weight / phenolic light stability Agent (trade name “Sumizer GP” manufactured by Sumitomo Chemical Co., Ltd.): 0.1 part by weight, UV absorber (trade name “Viosorb 591” manufactured by Kyodo Kagaku Co., Ltd.): 0.3 part by weight, antioxidant (joint Yakuhin Co., Ltd. product name “GSY-101P”): 0.05 parts by weight

<Embossed roll>
The embossed roll is made up of a “silicone rubber layer having the rubber hardness (JIS K 6253 durometer type A) and thickness (mm) shown in Table 1” and “adhesive layer” on the outer periphery of the “iron core portion having a diameter of 35 cm”. , “A fluororesin layer made of a fluororesin shown in Table 1 and having a thickness (mm) shown in Table 1” was sequentially laminated.
A surface design (embossed type) is formed on the fluororesin layer by sandblasting, and arithmetic average roughness (Ra) (μm) and maximum height roughness according to JIS B 0601-2001 (ISO 4287-1997) of each roll. (Rz) (μm) was as shown in Table 1.

Comparative Example 4
Instead of the embossed roll in Example 1, a stainless steel metal roll having a diameter of 40 cm was used to produce an ethylene copolymer resin sheet having a thickness of 450 μm.

Comparative Example 5
A “silicone rubber layer having the rubber hardness (JIS K 6253 durometer type A) and thickness (mm) shown in Table 1” is laminated on the outer periphery of the “iron core portion having a diameter of 35 cm”, and arithmetic operation is performed on the silicone rubber layer. Ethylene as in Example 1 except that an embossed roll having a surface design (embossed type) formed so that the average roughness (Ra) is 6.0 μm and the maximum height roughness (Rz) is 35 μm is used. A copolymer resin sheet was produced.

  About Examples 1-7 and Comparative Examples 1-5, the generation | occurrence | production situation, embossing property, and sheet | seat external appearance by which rubber was taken were evaluated, and the result is collectively shown in Table 1.

・ "Roll taken (rubber taken) occurrence status", the evaluation criteria are as follows according to the time taken until rubber taken.
Less than 8 hours: ×
8 to less than 48 hours: △
48 hours or more: ○

-"Emboss workability" evaluated visually the emboss workability of the obtained ethylene-type copolymer resin sheet except the comparative example 4. FIG.
The desired surface design was obtained: ○
Insufficient surface design: △

-The visual appearance of the obtained sheet was evaluated.
Good: ○
There are rare stripes and irregularities:
There are stripes and unevenness: ×

According to the embossing type roll for extrusion molding of the present invention, even if it is an ethylene-based copolymer resin containing an additive, no rubber is formed and an extruded sheet with good embossing and sheet appearance is obtained. be able to.
Accordingly, the embossing roll for extrusion molding according to the present invention and the ethylene copolymer resin sheet produced using the same are useful in various fields depending on the purpose and application. Suitable for sealing materials, solar cell backsheets and the like.

2 Shaft core 3 Silicone rubber layer 4 Fluororesin layer 10 Embossed roll for extrusion molding

Claims (4)

An embossing type roll for extrusion molding of an ethylene copolymer resin sheet,
A silicone rubber layer, an adhesive layer, and a fluororesin layer are sequentially laminated on the outer periphery of the shaft core, and the arithmetic average roughness (Ra) is 5.0 μm or more, and the maximum height roughness (Rz) is 25. An embossing roll for extrusion molding, which is ˜40 μm.   The embossing type | mold roll for extrusion molding of Claim 1 whose rubber hardness by JISK6253 durometer type A of the said silicone rubber is 30-80.   The embossing roll for extrusion molding according to claim 1 or 2, wherein the fluororesin layer has a thickness of 0.3 to 0.7 mm. It is the manufacturing method of the ethylene-type copolymer resin sheet using the embossing type | mold roll for extrusion molding as described in any one of Claims 1-3,
The method for producing an ethylene-based copolymer resin sheet, wherein an additive is added in an amount of 1 to 30 parts by weight with respect to 100 parts by weight of the ethylene-based copolymer resin.