JP2019083838A - Non-pressure-sensitive adhesive sheet for food processing apparatus, food processing apparatus, method of manufacturing food processing apparatus and surface modification method for food processing apparatus - Google Patents

Abstract

To provide non-pressure-sensitive adhesive sheet being a laminate of a fluorine resin layer and a base material layer for a food processing apparatus such as a rice cooking pot, a heating cooking utensil and a conveyor carrier for food product transport, the laminate having: good peeling strength between the fluorine resin layer and the base material layer; and a mechanical strength superior in comparison with coating, and the laminate enabling an effect by the fluorine resin layer to be continued.SOLUTION: The non-pressure-sensitive adhesive sheet for a food processing apparatus is provided that is a laminate obtained by bonding a resin sheet having polytetrafluoroethylene as a resin principal component with a base material sheet, and has a peeling strength between the resin sheet and the base material sheet of 3 N/mm or more.SELECTED DRAWING: None

Description

  The present invention relates to a non-adhesive sheet for food processing equipment. Further, the present invention relates to a food processing apparatus including a rice cooker, a heating cooker, and a conveyor for conveying a food, a method for manufacturing the food processing apparatus of the food processing apparatus, and a surface modification method for the food processing apparatus.

In food processing equipment, in particular rice cookers, conveyers for conveyors and pans, in order to impart moldability or non-stickiness to food, coat the surface that comes in contact with food with fluorine resin with fluorine resin etc. And the like have been proposed (patent documents 1 to 3). On the other hand, in factories etc. producing rice, a large amount of rice cookers made of iron or aluminum castings are prepared, and a large amount of rice is cooked (patent documents 4). Moreover, the conveyor which provided the flat conveyance body for conveying a raw material or processed food is generally known (patent document 5).

  In addition, various techniques relating to a laminate in which a fluorine-based resin layer is provided on the surface of a base material have been proposed (Patent Documents 6 to 8)

JP 2008-36377 A Unexamined-Japanese-Patent No. 2003-199675 Japanese Patent Application Laid-Open No. 52-140174 JP 2012-179541 A Japanese Utility Model Application Publication No. 6-61829 Japanese Patent No. 5884358 Patent No. 4244286 Patent No. 6149739 gazette

By applying the inventions described in Patent Documents 1 to 3 to a rice cooker, a superheated cooking appliance, and a conveyer for conveying a food, a certain effect in releasability with food can be obtained, but these are continued Or durability is required in order to use it continuously. Since a fluorocarbon resin, particularly polytetrafluoroethylene (hereinafter referred to as PTFE), has high non-adhesiveness, adhesion of raw materials and the like can be suppressed, but bonding with a substrate is generally difficult. In addition, since the PTFE coating is easily worn, it is necessary to have a certain mechanical strength and to be able to ensure a certain thickness. That is, it is required that the coating or the like of the fluorine resin does not easily peel off and the effect can be sustained. Furthermore, since the coating process requires large-scale equipment, there has been a problem that these apparatuses or tools have to be brought in to the factory where the coating process can be performed.

  Here, Patent Document 1 describes a frying pan with a three-layer fluororesin coat. Further, in Patent Document 2, the aluminum material of the inner pot of the rice cooker is coated with a fluorine resin containing PFA (tetrafluoroethylene) as a main ingredient. However, these are only those coated with a fluorine resin on a base material such as metal, and it can not be said that they are coated with a fluorine resin with a certain peel strength and thickness. Therefore, there was a problem that it could not stand the wear by repeated use. In particular, in parts of a food processing apparatus that continuously cooks a large amount of food for a long time, there is a problem that the fluorine resin coating is immediately peeled off. In addition, although the cited reference 3 describes the food processing conveyor / campus that constitutes the transport section by the campus base consisting of the warp and weft of the fluorocarbon resin monofilament, since it is a filament, it is used for a long time Since the filament wears out, durability and abrasion resistance can not be expected. Furthermore, in the food conveyance conveyor, when conveying a food to which oil such as fried food is attached, the oil remains on the conveyor conveyance body, and there is a problem that the maintenance frequency of wiping the oil increases.

  Further, Patent Document 6 discloses a method of manufacturing a laminate having a step of laminating a resin sheet made of modified PTFE and a metal layer and performing heat pressing. However, joining undenatured PTFE to a metal layer is not disclosed. Further, the bonding strength between the resin sheet made of modified PTFE and the metal layer is about 20 N / 3 inch, which is not sufficient. Patent Document 7 discloses a laminate in which a fluorine resin film layer and a metal plate are laminated via a specific ethylene copolymer composition layer. However, in the examples, the adhesive strength with a film of ethylene-tetrafluoroethylene copolymer which is less non-tacky than PTFE is at most about 2 N / mm in the 180 ° C. peel test, which is not sufficient. . Patent Document 8 discloses a laminate in which a specific primer layer and a top coat layer made of a fluorine resin are laminated in this order on the surface of a substrate. However, it is not disclosed that the top coat layer is a sheet, and the thickness of the top coat layer is increased, and it is used as a food processing apparatus such as a rice cooker, a heating cooker, and a conveyor for food conveyance. There are limits to sustaining the effect.

  As described above, Patent Documents 1 and 2 disclose that in a non-adhesive sheet for food processing apparatus, formation of a fluororesin layer such as PTFE on the surface of a substrate is disclosed, but the peel strength of both is disclosed. Is not considered at all or there is room for improvement. In addition, although Patent Document 3 discloses a container food body for food processing comprising a conveyer / campus in which the base material transfer portion is made of a fluorocarbon monofilament, there is room for improvement in durability and wear resistance. Moreover, although the laminated body which provided the fluorine resin layer in the base-material surface is disclosed by patent documents 6-8, in the invention of patent documents 6 and 7, peeling strength is still insufficient again, and patent documents In the invention described in 8, there is a limit to sustaining the effect of the top coat layer made of fluorocarbon resin.

  Then, the object of the present invention is a layered product of a fluorocarbon resin layer and a substrate layer for food processing devices, such as a rice cooker, a heating cooker, a conveyer for food conveyance, etc. And peel strength is good, and the effect of the fluorocarbon resin layer is made sustainable.

  As a result of intensive investigations conducted by the present inventor, it is possible to use a resin sheet whose main resin component is PTFE as the fluorine resin layer, and use a base material sheet as the base material layer, so that the peel strength of the both becomes equal to or more than a predetermined value. As a result, the inventors have found that the above-mentioned problems can be solved by joining them to complete the present invention. The means for solving the problems of the present invention are as follows.

(1)
It is a laminated body in which a resin sheet whose main resin component is polytetrafluoroethylene and a substrate sheet are joined, and the peel strength between the resin sheet and the substrate sheet is 3 N / mm or more, not for food processing apparatus Adhesive sheet.

(2)
The non-adhesive sheet for the food processing apparatus according to (1), wherein the food processing apparatus is a rice cooker, a heating cooker or a conveyor for food conveyance.

(3)
The non-adhesive sheet for food processing apparatuses according to (1) or (2), wherein the resin sheet and the base sheet are joined via an adhesive.

(4)
The non-adhesive sheet for food processing apparatus according to any one of (1) to (3), wherein the thickness of the resin sheet is 0.5 mm or more.

(5)
The non-adhesive sheet for food processing apparatus according to any one of (1) to (4), wherein a fixing part for fixing to the food processing apparatus is formed on the substrate sheet.

(6)
The non-adhesive sheet | seat for food processing apparatuses in any one of (1)-(5) whose adhesive agent is an adhesive fluorine-containing copolymer.

(7)
The food processing apparatus provided so that the resin sheet side of the non-adhesive sheet in any one of (1)-(6) may turn into the side which a foodstuff contacts.

(8)
The rice cooker provided so that the resin sheet side of the non-adhesive sheet in any one of (1)-(6) may turn into the side which rice contacts.

(9)
The cooking-equipment provided so that the resin sheet side of the non-adhesive sheet in any one of (1)-(6) might be in the side which a foodstuff contacts, and / or the side which cooks a foodstuff.

(10)
The conveyance body for the conveyor for foodstuffs conveyance provided so that the resin sheet side of the non-adhesive sheet in any one of (1)-(6) might be in contact side of foodstuffs.

(11)
(4) A method for producing a non-adhesive sheet for a food processing apparatus as described in the above,
A method for producing a non-adhesive sheet, comprising the step of bonding a resin sheet having a thickness of 0.5 mm or more and a base sheet to a peel strength of 3 N / mm or more.

(12)
The non-adhesive sheet for the food processing apparatus according to any one of (1) to (6) is installed on the food contact surface and / or the heating / cooking surface according to the shape of the non-adhesive sheet. A method of manufacturing a food processing apparatus, comprising coating at least a part and imparting non-tackiness to a sliding surface.

(13)
The non-adhesive sheet for the food processing apparatus according to any one of (1) to (6) is installed on the food contact surface and / or the heat cooking surface according to the shape, and the food contact surface And / or a method of surface modification of a food processing apparatus, which covers at least a part of the cooking surface and imparts non-tackyness to the food contact surface and / or the cooking surface.

(14)
The conveyer for a conveyor for food conveyance which provided the non-adhesive sheet which consists of a layered product with which a resin sheet whose resin main ingredient is polytetrafluoroethylene was joined with a substrate sheet so that it might be in contact with food.

  According to the present invention, food processing has good peel strength between a resin sheet whose main resin component is PTFE and a substrate sheet, and can maintain the effect of the resin sheet based on PTFE favorably. It is possible to provide a non-adhesive sheet for the device. Therefore, the non-adhesive sheet is suitable for, for example, a rice cooker, a heating cooker, and a conveyer for food conveyance.

  Hereinafter, embodiments of the present invention will be described.

  In the embodiment of the present invention, the non-adhesive sheet for a food processing apparatus is a laminate in which a resin sheet whose main resin component is PTFE and a base sheet are joined. And the peeling strength of the joined resin sheet and a base material sheet is 3 N / mm or more. In the following, unless otherwise specified, a resin sheet whose main resin component is PTFE is referred to as a PTFE sheet.

  As described above, since the peel strength between the PTFE sheet and the base sheet is equal to or more than a predetermined value, the PTFE sheet is well bonded to the base sheet even when the non-adhesive sheet is used for a food processing apparatus. Further, as described later, for example, since it is possible to bend the non-adhesive sheet without peeling off the PTFE sheet from the base sheet, depending on the constituent material of the base sheet, desired sites for various uses It is possible to process according to the shape of and install. Moreover, since lamination is performed using a PTFE sheet formed in advance, it is possible to increase the thickness as compared with the case where the powder of PTFE is sintered on the surface of the base sheet as described in, for example, Patent Document 8 It is. In addition, the PTFE sheet is superior in mechanical strength to the coating. Therefore, it is possible to maintain the effect by the PTFE sheet better than such conventional techniques. Furthermore, non-adhesive sheets can be easily made non-adhesive on surfaces that come in contact with food etc. simply by installing them on surfaces that come in contact with food, such as rice cookers, cooking utensils, conveyers for conveying food, etc. It can be granted. Therefore, for example, installation of a non-adhesive sheet on an existing machine or the like is easy, and when the non-adhesiveness decreases after long-term use, the non-adhesive sheet is replaced to change the original non-adhesive on the sliding surface. It can be easily given.

  The PTFE sheet is formed by using PTFE as a resin main component.

  PTFE exhibits excellent chemical resistance, shows no dissolution or swelling with almost all chemicals, and exhibits excellent stability only by being attacked by molten metal sodium or high temperature high concentration fluorine gas. It has excellent heat resistance, a melting point of about 327 ° C., a continuous use temperature of about 260 ° C., which is extremely high in organic materials, and mechanical strength hardly decreases even when left at 250 ° C. for a long time. Furthermore, its surface properties show excellent hydrophobicity, oleophobicity and non-stickiness.

  As described above, PTFE is excellent in chemical resistance, heat resistance, hydrophobicity, oleophobicity, non-adhesiveness, and high in safety to the human body. Therefore, PTFE sheet is used for rice cooker, cooking utensils, food conveyance, etc. In the application for food processing apparatuses, such as a conveyer, by being provided on a surface or the like in contact with food, remaining of food deposits, oil stains, or the like on the surface or the like in contact with food can be suppressed.

  The PTFE sheet is previously formed into a sheet shape. Since PTFE only gels upon heating and does not exhibit fluidity, it is not easy for general injection molding and extrusion molding. Therefore, it is formed by, for example, a sintering method or a paste extrusion method. Known methods can be adopted as these methods. In the sintering method, for example, a powder of PTFE is placed in a mold and pressurized, and firing is performed at a temperature equal to or higher than the melting point of PTFE. If necessary, it may be transferred to another mold immediately after being in the form of a clear gel and subjected to secondary forming. Further, after molding, machining may be performed to obtain a desired shape. In the paste extrusion method, an organic solvent or the like is added to the PTFE powder to make it into a paste, and after it is made into a sheet by a calender, the solvent is volatilized and then firing is performed. As a method other than the sintering method and the paste extrusion method, for example, a cylindrical or prismatic molded body is cut into a sheet, or a suspension of PTFE is cast on a flat surface and then sintered to form a sheet. Methods etc.

  The thickness of the PTFE sheet can be set in consideration of each application. From the viewpoint of continuously obtaining various effects such as abrasion resistance and durability by the above-mentioned PTFE, 0.3 mm or more is preferable, 0.5 mm or more is more preferable, 1 mm or more is more preferable, and 3 mm or more is particularly preferable.

  The main component of the PTFE sheet is PTFE, but other additives may be added in addition to the resin component. As an additive, a coloring agent, a reinforcing material, a lubricity imparting agent, an antibacterial agent, a photocatalyst etc. are mentioned, for example.

  As a material which constitutes a substrate sheet, it can choose suitably according to each use of a food processing device. Examples of such a material include metals such as iron, steel, aluminum, copper, gold and silver, ceramic, glass, synthetic resin, natural resin, wood, paper, diamond and the like. The steel may be an alloy of iron containing 2.0% or less of carbon and other elements, and examples thereof include stainless steel and the like. Synthetic resins include fiber reinforced resins such as carbon fiber reinforced resins and glass fiber reinforced resins. Among them, stainless steel, aluminum and iron are preferable from the viewpoint of corrosion resistance, weight and versatility.

  The thickness of the substrate sheet can be set in consideration of the respective applications and constituent materials. As described later, when using a non-adhesive sheet by bending or the like, the thickness can be determined according to the characteristics of the constituent material of the base sheet. When the constituent material is metal, for example, it can be 0.1 to 5.0 mm.

  The base sheet may have a fixing portion for fixing a non-adhesive sheet of a predetermined use to a food processing apparatus such as a rice cooker, a heating cooker, a conveyer for food conveyance, and the like. By forming the fixing portion, the non-adhesive sheet can be easily fixed in a short time to a food processing apparatus such as a rice cooker, a heating cooker, or a conveyor for a food conveyance without coating treatment. it can. Therefore, for example, existing rice cookers and machines equipped with these, existing cooking devices, machines equipped with these, etc., and conveyers for food conveyance conveyors and machines equipped with these are provided with non-stickiness. The sliding surface thus formed can be easily formed in a short time. That is, the food processing apparatus is often used in a large scale factory and is a relatively large member in many cases, so it is difficult to carry. However, by adopting the above-mentioned configuration, a large scale coating facility Even if it is not used, it can be easily installed in a short time, for example, in a customer's food factory, regardless of location. As such a fixing portion, for example, a through hole for fixing to a food processing apparatus such as a rice cooker, a heating cooker, a conveyer for food conveyance or the like by a bolt, a nut or a rivet, a female screwed with an external screw Food processing apparatus such as a clip for holding a predetermined portion of a food processing apparatus such as a screw hole, a rice cooker, a heating cooker, a conveyor for food conveyance, a rice cooker, a heating cooker, a conveyor for food conveyance It is fitted in the concave part provided in the predetermined part of the food processing device such as the projection receptacle, the rice cooker, the heating cooker, the conveyer for food conveyance, etc. which engages with and holds the projection provided in the predetermined part. And the like. Such a fixing portion can be provided at one or two or more places depending on the application and the like. The installation position of the fixing portion can also be determined according to the application and the like.

  Thus, although a fixing | fixed part may be provided in a base material sheet, when the material which comprises a base material sheet can be welded, the non-adhesive sheet of a predetermined use is a rice cooker by welding a base material sheet. You may fix to food processing apparatuses, such as a heating cooker and the conveyance body for conveyors for food conveyance. In this case, it is preferable to select the shape of the substrate sheet in consideration of the fixing site or to control the output of the welding apparatus so that the PTFE sheet is not excessively heated.

  The peel strength between the PTFE sheet and the base sheet is 3 N / mm or more. There is no particular upper limit to the peel strength, as it is generally better. Such peel strength can be measured, for example, by the peel strength test of the adhesive tape-adhesive sheet test method. The test conditions at that time can be performed according to JIS Z 0237. In the present invention, the peel strength is a value obtained by dividing the measured value by the width of the test piece.

  There is no particular limitation on the method of bonding the PTFE sheet and the base sheet so as to have such peel strength, for example, a method of surface-treating the bonding surface of both sheets and then crimping the both, via an adhesive The method of joining etc. are mentioned. As the adhesive, it is preferable to use one having affinity to both the base sheet and the PTFE sheet. By using such an adhesive, surface treatment of both sheets can be omitted. Moreover, it is preferable that the whole joining surface of the PTFE sheet is joined to the base sheet.

  As described above, the PTFE sheet has excellent non-stickiness and tends to be difficult to bond, so it is preferable to select an adhesive having good affinity to PTFE. As such an adhesive, an adhesive fluorine-containing copolymer can be illustrated. Examples of the adhesive fluorine-containing copolymer include those described in Japanese Patent No. 4424246, Japanese Patent No. 536539, and Japanese Patent No. 5263269. These adhesive fluorine-containing copolymers are shown below.

  The adhesive fluorine-containing copolymer has a repeating unit (a) based on tetrafluoroethylene (hereinafter referred to as TFE) and / or chlorotrifluoroethylene (hereinafter referred to as CTFE), and a dicarboxylic acid anhydride group and The repeating unit (b) and other monomers based on a cyclic hydrocarbon monomer having a polymerizable unsaturated group in the ring (but excluding the monomer when overlapping with repeating units (a) and (b)) And the repeating unit (c).

  In the adhesive fluorine-containing copolymer, the repeating unit (a) is 50 to 99.89% by mole based on the total molar amount of the repeating unit (a), the repeating unit (b) and the repeating unit (c), The repeating unit (b) is 0.01 to 5 mol%, and the repeating unit (c) is 0.1 to 49.99 mol%. The repeating unit (a) is preferably 50 to 99.47 mol%, the repeating unit (b) is 0.03 to 3 mol%, and the repeating unit (c) is preferably 0.5 to 49.97 mol%, more preferably Is 50 to 98.95 mol% of the repeating unit (a), 0.05 to 2 mol% of the repeating unit (b), and 1 to 49.95 mol% of the repeating unit (c). When the mole percentage of the repeating unit (a), the repeating unit (b) and the repeating unit (c) is in this range, the adhesive fluorine-containing copolymer is excellent in heat resistance and chemical resistance. Furthermore, when the molar percentage of the repeating unit (b) is in this range, the adhesive fluorine-containing copolymer is a substrate sheet and a PTFE sheet of constituent materials such as thermoplastic resins other than the adhesive fluorine-containing copolymer. Excellent adhesion to When the molar percentage of the repeating unit (c) is in this range, the adhesive fluorine-containing copolymer is excellent in moldability and mechanical properties such as stress crack resistance.

  The “cyclic hydrocarbon monomer having a dicarboxylic acid anhydride group and having a polymerizable unsaturated group in the ring” (hereinafter simply referred to simply as “cyclic hydrocarbon monomer”) has one or more 5-membered rings or 6 It is a cyclic hydrocarbon comprising a member ring, and further a polymerizable compound having a dicarboxylic acid anhydride group and an endocyclic polymerizable unsaturated group. The cyclic hydrocarbon is preferably a cyclic hydrocarbon having one or more bridged polycyclic hydrocarbons. That is, a cyclic hydrocarbon comprising a bridged polycyclic hydrocarbon, a cyclic hydrocarbon formed by condensation of two or more of the bridged polycyclic hydrocarbon, or a cyclic hydrocarbon formed by condensation of a bridged polycyclic hydrocarbon and another cyclic hydrocarbon Is preferred. Further, this cyclic hydrocarbon monomer has one or more endocyclic polymerizable unsaturated groups, that is, polymerizable unsaturated groups present between carbon atoms constituting the hydrocarbon ring. The cyclic hydrocarbon monomer further has a dicarboxylic acid anhydride group (-CO-O-CO-), and the dicarboxylic acid anhydride group may be bonded to two carbon atoms constituting the hydrocarbon ring, It may be bonded to the other two carbon atoms. Preferably, the dicarboxylic acid anhydride group is a carbon atom constituting the ring of the cyclic hydrocarbon and is bonded to two adjacent carbon atoms. Furthermore, in place of a hydrogen atom, a halogen atom, an alkyl group, a halogenated alkyl group, or another substituent may be bonded to a carbon atom constituting a ring of a cyclic hydrocarbon.

  As the specific example, it is represented by Formula (1)-(8). Here, R in the formulas (2) and (5) to (8) is a lower alkyl group having 1 to 6 carbon atoms, a fluorine atom, a chlorine atom, a halogen atom selected from a bromine atom and an iodine atom, and the lower The hydrogen atom in an alkyl group shows the halogenated alkyl group substituted by the halogen atom.

  As the above-mentioned cyclic hydrocarbon monomer, 5-norbornene-2,3-dicarboxylic acid anhydride (hereinafter referred to as NAH) represented by the formula (1), preferably a table of the formulas (3) and (4) The cyclic hydrocarbon monomer which is an acid anhydride, and the cyclic hydrocarbon monomer whose substituent R is a methyl group in the formulas (2) and (5) to (8). More preferably, it is NAH.

As other monomers, vinyl fluoride, vinylidene fluoride (hereinafter referred to as VdF), CTFE (except when used as a repeating unit (a)), trifluoroethylene, hexafluoropropylene (hereinafter referred to as, HFP.), CF ₂ CCFOR ^{f 1} (where R ^f 1 is a perfluoroalkyl group having 1 to 10 carbon atoms and optionally containing an oxygen atom between carbon atoms), CF ₂ CCFOR ^f ₂ SO ₂ X ¹ (R ^f2 is a perfluoroalkylene group having 1 to 10 carbon atoms and may contain an oxygen atom between carbon atoms, X ¹ is a halogen atom or a hydroxyl group), CF ₂ CCFOR ^f ₂ CO ₂ X ² (wherein R ^f2 is the same as above) the same, ^{X 2} is an alkyl group having 1 to 3 carbon hydrogen atom or a _{C.), CF 2 = CF (} CF 2) p OCF = CF 2 ( wherein, p 1 or ^{_{2.), CH 2 = CX}} 3 (CF 2) q X 4 ( wherein, ^{X 3} and ^{X 4} are each independently a hydrogen atom or a fluorine atom, q is 2 to 10 integers.), Perfluoro ( 2-methylene-4-methyl-1,3-dioxolane), olefins having 2 to 4 carbon atoms such as ethylene, propylene and isobutene, vinyl esters such as vinyl acetate, and vinyl ethers such as ethyl vinyl ether and cyclohexyl vinyl ether. The other monomers may be used alone or in combination of two or more.

As a specific example of CF ₂ = CFOR ^{f 1} , for example, CF ₂ = CFOCF ₂ CF ₃ , CF ₂ = CFOCF ₂ CF ₂ CF ₃ , CF ₂ = CFOCF ₂ CF ₂ CF ₂ CF ₃ , CF ₂ = CFO (CF _{2 8} F etc. may be mentioned. _Preferably, a _{CF 2 = CFOCF 2 CF 2 CF} 3.

^{_{CH 2 = CX 3 (CF 2}} ) Examples of q ^{X 4} may, for _{example, CH 2 = CH (CF 2} ) 2 F, CH 2 = CH (CF 2) 3 F, CH 2 = CH (CF 2) ₄ F, CH ₂ CFCF (CF ₂ ) ₃ H, CH ₂ CFCF (CF ₂ ) ₄ H, and the like. Preferably, CH ₂ CHCH (CF ₂ ) ₄ F or CH ₂ CHCH (CF ₂ ) ₂ F.

Other monomers, preferably, VdF, HFP, CTFE (excluding, however, the case where they are used as a repeating unit ^{_{(a).), CF 2}} = CFOR f1, CH 2 = CX 3 (CF 2) q X 4 At least one member selected from the group consisting of ethylene, propylene and vinyl acetate, more preferably HFP, CTFE (except when used as a repeating unit (a)), CF ₂ = CFOR ^{f 1} , It is at least one selected from the group consisting of ethylene and CH ₂ = CX ³ (CF ₂ ) _q X ⁴ . Most preferably, HFP or CF ₂ = CFOR ^f1 . _As the CF 2 = CFOR ^f1, preferably ^{R f1} is perfluoroalkyl group having 1 to 6 carbon atoms, more preferably a perfluoroalkyl group having 2 to 4 carbon atoms, perfluoropropyl group is most preferred.

Specific examples of the adhesive fluorine-containing copolymer include, for example, TFE / CF ₂ CCFOCF ₂ CF ₂ CF ₃ / NAH copolymer, TFE / HFP / NAH copolymer, TFE / CF ₂ CCFOCF ₂ CF ₂ CF ₃ / HFP / NAH copolymer, TFE / VdF / NAH copolymer, TFE / CH ₂ CHCH (CF ₂ ) ₄ F / NAH / ethylene copolymer, TFE / CH ₂ CHCH (CF ₂ ) ₂ F / NAH / ethylene copolymer, CTFE / CH ₂ CHCH (CF ₂ ) ₄ F / NAH / ethylene copolymer, CTFE / CH ₂ CHCH (CF ₂ ) ₂ F / NAH / ethylene copolymer, CTFE / CH ₂ CHCH (CF ₂ ) ₂ F / NAH / ethylene copolymer and the like.

  150-320 degreeC is preferable and, as for melting | fusing point of an adhesive fluorine-containing copolymer, 200-310 degreeC is more preferable. The melting point can be adjusted by appropriately selecting the content ratio of the repeating unit (a), the repeating unit (b) and the repeating unit (c) within the above range.

  An adhesive fluorine-containing fluorine-containing copolymer having an adhesive functional group such as an ester group, a carbonate group, a hydroxyl group, a carboxyl group, a carbonyl fluoride group or an acid anhydride residue as a polymer terminal group of the adhesive fluorine-containing copolymer It is preferable because it is excellent in adhesion to a substrate sheet of a constituent material such as a thermoplastic resin other than a copolymer and a PTFE sheet. The polymer terminal group having the adhesive functional group can be introduced by appropriately selecting a radical polymerization initiator, a chain transfer agent, and the like at the time of production of the adhesive fluorocopolymer.

The adhesive fluorine-containing copolymer can have a volumetric flow rate (hereinafter referred to as Q value) of 0.1 to 1000 mm ³ / sec. The Q value is an index that represents the melt flowability of the adhesive fluorine-containing copolymer, and is an index of the molecular weight. The larger the Q value, the lower the molecular weight, and the smaller the Q value, the higher the molecular weight. Q value is adhesion when extruded into an orifice with a diameter of 2.1 mm and a length of 8 mm under a load of 7 kg at a temperature 50 ° C. higher than the melting point of the adhesive fluorine-containing copolymer using a flow tester made by Shimadzu Corporation Rate of the fluorocarbon copolymer. When the Q value is too small, extrusion molding becomes difficult, and when it is too large, the mechanical strength of the adhesive fluorocopolymer decreases. Q values of the adhesive fluorocopolymer is preferably from 5 to 500 mm ³ / sec, 10 to 200 mm ³ / sec is more preferable.

The method for producing the adhesive fluorine-containing copolymer is not particularly limited, and a radical polymerization method using a radical polymerization initiator is used. As a polymerization method, bulk polymerization, solution polymerization using an organic solvent such as fluorohydrocarbon, chlorohydrocarbon, fluorochlorohydrocarbon, alcohol, hydrocarbon and the like, an aqueous medium and, if necessary, an appropriate organic solvent are used. Suspension polymerization, emulsion polymerization using an aqueous medium and an emulsifying agent, and solution polymerization is particularly preferable.

As a radical polymerization initiator, the radical polymerization initiator whose temperature whose half life is 10 hours is 0 degreeC-100 degreeC is preferable. More preferably, it is 20-90 ° C. Specific examples thereof include azo compounds such as azobisisobutyronitrile, non-fluorinated diacyl peroxides such as isobutyryl peroxide, octanoyl peroxide, benzoyl peroxide, lauroyl peroxide and the like, diisopropyl peroxydicarbonate, di-n-propyl Peroxydicarbonates such as peroxydicarbonate, tert-butylperoxypivalate, tert-butylperoxyisobutyrate, peroxyesters such as tert-butylperoxyacetate, (Z (CF ₂ ) _r COO) ₂ (where Z is Fluorine-containing diacyl peroxides such as a compound represented by a hydrogen atom, a fluorine atom or a chlorine atom, and r is an integer of 1 to 10), potassium persulfate, sodium persulfate, ammonium persulfate and the like Peroxides and the like.

When controlling the Q value of the adhesive fluorine-containing copolymer, it is also preferable to use a chain transfer agent. Examples of chain transfer agents include alcohols such as methanol and ethanol, chlorofluorohydrocarbons such as 1,3-dichloro-1,1,2,2,3-pentafluoropropane and 1,1-dichloro-1-fluoroethane, Examples thereof include hydrocarbons such as pentane, hexane and cyclohexane. As a chain transfer agent for introducing an adhesive functional group to the polymer terminal of the adhesive fluorine-containing copolymer, acetic acid, acetic anhydride, methyl acetate, ethylene glycol, propylene glycol and the like can be mentioned.

  The polymerization conditions of the adhesive fluorine-containing copolymer are not particularly limited, and the polymerization temperature is preferably 0 to 100 ° C, and more preferably 20 to 90 ° C. The polymerization pressure is preferably 0.1 to 10 MPa, and more preferably 0.5 to 3 MPa. The polymerization time is preferably 1 to 30 hours.

  The concentration of the cyclic hydrocarbon monomer in the polymerization is preferably 0.01 to 5 mol%, more preferably 0.1 to 3 mol%, and most preferably 0.1 to 1 mol% with respect to the total monomers. When the concentration of the cyclic hydrocarbon monomer is too high, the polymerization rate tends to decrease. When it is in the above range, the polymerization rate at the time of production does not decrease, and the fluorine-containing copolymer is excellent in adhesiveness. During the polymerization, as the cyclic hydrocarbon monomer is consumed in the polymerization, it is preferable to continuously or intermittently supply the consumed amount into the polymerization tank to maintain the concentration of the cyclic hydrocarbon monomer in this range.

The adhesive fluorine-containing copolymer obtained by the production method as described above can be obtained in the form of pellets, powder or other according to a conventional method. Since the adhesive fluorine-containing copolymer is excellent in moldability, it can be injection-molded or extrusion-molded and can be molded into a desired shape.
In addition, since the above-mentioned adhesive fluorine copolymer is excellent in flexibility, a sheet molded product using them as an adhesive suppresses peeling of the laminated sheet even if bending or drawing is performed. it can.

  The adhesive fluorine-containing copolymer can be produced as described above, but a commercially available product can be used. For example, EA-2000 manufactured by Asahi Glass Co., Ltd., etc. may be mentioned.

  The form of the adhesive is not particularly limited, and examples thereof include powder, paste, liquid, sheet and the like. When the adhesive is the above-mentioned adhesive fluorine-containing copolymer, a molded article of a sheet can be used.

  When an adhesive is used, the thickness of the adhesive is preferably 5 to 100 μm, and more preferably 25 to 100 μm, from the viewpoint of securing a predetermined peel strength or more, depending on the type.

  The shape of the non-adhesive sheet for a predetermined use is not particularly limited, and examples thereof include flat plates, curved plates, and tubes. Moreover, it is also possible to form beforehand the shape suitable for the use of food processing apparatuses, such as a rice cooker, a heating cooker, the conveyance body for conveyers for food conveyance, and to use it directly as a component of each use. In applications of food processing devices such as kettles, cooking utensils, conveyers for conveying food, etc., it is also possible to make it a shape that can be installed later on an existing surface in contact with food. Such a shape may be formed by forming the substrate sheet into a desired shape and subjecting it to heat and pressure treatment, or by subjecting a flat non-adhesive sheet to bending or cutting. it can. Food processing devices such as rice cookers, cooking utensils, conveyers for conveying food, etc. and parts thereof may be variously shaped according to the needs of customers, so they are processed according to their shapes. In the case, it may be a flat plate. Since the non-adhesive sheet for a predetermined use has a peeling strength equal to or higher than a predetermined value, peeling of the PTFE sheet and the base sheet can be suppressed even if bending or drawing processing is performed.

  The method for producing a non-adhesive sheet for a predetermined use includes the step of bonding a preformed PTFE sheet and a base sheet such that the peel strength between them is 3 N / mm or more. It is as follows when the case where an adhesive agent is used is demonstrated.

  First, a PTFE sheet is formed. Then, an adhesive is disposed between the desired base sheet and the PTFE sheet, and if necessary, surface treatment, heating and pressing of both sheets are performed so that both sheets have a predetermined peel strength. A bonded laminate is obtained. The thickness of the PTFE sheet is preferably 0.5 mm or more.

  When the above-mentioned adhesive fluorine-containing copolymer is used as an adhesive, various forms such as powder, pellet, sheet and the like can be used, but from the viewpoint of control of peeling strength, it is preferable to use a sheet. . The thickness of the sheet is preferably 5 to 100 μm, and more preferably 25 to 100 μm, from the viewpoint of adhesion stability and cost. In addition, as described above, the adhesive fluorine-containing copolymer has a good affinity to the PTFE sheet, so the surface treatment of the PTFE sheet is unnecessary. In addition, since the affinity to metals and organic substances is also good, when the material of the substrate sheet is those, surface treatment is unnecessary. Moreover, it is preferable to heat to the temperature more than the melting | fusing point of PTFE, Preferably, it is 330-400 degreeC, It is more preferable to perform a pressurization process in the state heated at such temperature. The pressure treatment is preferably 0.1 to 10 MPa.

  The non-adhesive sheet described above is provided on the surface of the food processing apparatus, such as a rice cooker, a heating cooker, and a conveyor for conveying food, which contacts the food. Thereby, non-adhesiveness can be given to the surface which touches each food.

  The rice cooker includes an inner pot for cooking rice (see, for example, Patent Documents 1 and 4). And the above-mentioned non-adhesive sheet is installed in the part which the raw rice or the cooked rice inside the inner pot touches, and the surface where the PTFE sheet comes in contact with the raw rice or the cooked rice comes into contact.

  PTFE is particularly suitable for food processing equipment because it is highly safe for the human body. In addition, since the adhesive fluorine-containing copolymer described above is also highly safe, when it is used as an adhesive, the safety is further improved.

  Installation of the non-adhesive sheet for rice cooker is, for example, installing in advance or after the non-adhesive sheet according to the shape on the surface of the rice cooker on which the cooked rice comes in contact, at least a part of the surface on which the food comes in contact. It is done by covering the whole. Thereby, the manufacture of a rice cooker or the modification | reformation of the surface which the boiled rice touches can be performed. The rice cooker generally has a bottomed cylindrical shape such as a cube or a pyramid shape. Therefore, for example, in the case of a cubic body or a truncated pyramidal bottomed cylindrical shape, a non-adhesive sheet is formed by performing deep drawing bending processing into a predetermined shape, and the formed product is fixed to the inner pot of the rice cooker. Thus, the non-adhesive sheet of the present invention can be coated on the entire rice cooker. Further, for example, a plurality of strip-like flat non-adhesive sheets are continuously arranged on the surface of the rice cooker in contact with the cooked rice, and the entire surface in contact with the cooked rice is covered without gaps, and the fixing portion formed on the base sheet Can also be fixed to the rice cooker. Of course, in these production methods, the non-adhesive sheet is adjusted to have mechanical strength suitable for rice cooker applications.

  The cooking appliance corresponds to a factory or household frying pan, a cooking pot, an oven, a top plate for an electromagnetic cooking appliance, a frying fryer and the like. And the above-mentioned non-adhesive sheet is installed so that a PTFE sheet may be in contact with food.

For example, in the case of a frying pan, the non-adhesive sheet for heating and cooking utensils is installed in advance or after the non-adhesive sheet according to the shape on the side where food is in contact and / or the side to be cooked. It is carried out by coating at least a part, preferably the whole, of the surface and / or the surface to be cooked (see, for example, Patent Document 1). This makes it possible to modify the food contact surface and / or the surface to be cooked. The frying pan generally has a shape such as a bowl shape. Therefore, for example, the non-adhesive sheet is formed by performing deep drawing bending into a predetermined shape, and the formed article is fixed to the inner pot of the rice cooker, whereby the non-adhesive sheet of the present invention is spread over the entire rice cooker. It can be coated. Also, for example, a plurality of strip-like flat non-adhesive sheets are continuously arranged on the food contact surface and / or the cooking surface of the cooking device, and the entire food contact surface and / or the cooking surface. It can also be fixed to a cooking appliance with a fixing portion formed on a substrate sheet without covering with a gap.

The food conveying conveyor is composed of a driving body and a plurality of plate-like conveying bodies. (See, for example, Patent Document 5). And the above-mentioned non-adhesive sheet is installed so that a PTFE sheet may be arranged in the portion which the food of the conveyance body contacts, ie, the conveyance side which installs food.

For the installation of the non-adhesive sheet for the conveyor for food conveyance, for example, at least the surface on which the non-adhesive sheet cut in accordance with the shape of the conveyance is placed in advance or subsequently on the surface in contact with food. It is carried out by covering a part, preferably the whole. This makes it possible to modify the surface in contact with the food. In addition, for example, a plurality of strip-like flat non-adhesive sheets are continuously arranged on the food contact surface, and the entire food contact surface is covered without gaps, and the fixing portion formed on the base sheet It can also be fixed to the conveyer for the conveyer.

  The non-adhesive sheet of the above-mentioned predetermined use is installed in food processing equipment such as rice cooker, heating cooker, conveyor for food conveyance, etc., and after the effect of the PTFE sheet decreases, replace the non-adhesive sheet Can be easily reproduced.

  Hereinafter, based on an example, a detailed embodiment is described.

Example 1
PTFE sheet (manufactured by Starlight Industries, product name # 31000, length 100 mm, width 16 mm, thickness 0.5 mm), base material sheet made of iron (length 100 mm, width 16 mm, thickness 1.0 mm), adhesive Use a sheet of adhesive fluorine-containing copolymer (manufactured by Asahi Glass Co., Ltd., EA-2000, length 30 mm, width 16 mm, thickness 0.05 mm) to match the PTFE sheet with the iron sheet in the length and width direction As shown in FIG. 6A, the adhesive was placed at one end between the two, and placed in a press (a bench test press manufactured by Tester Sangyo Co., Ltd.). The mold temperature was set to 360 ° C., heated and pressurized at 3 MPa for 200 seconds, and then cooled to obtain a non-adhesive sheet in which the PTFE sheet and the base sheet were joined. The obtained non-adhesive sheet was used for the peeling test.

(Examples 2 to 4)
A non-adhesive sheet was obtained in the same manner as in Example 1 except that a sheet of the material shown in Table 1 was used instead of the iron sheet. In Table 1, "SUS" is a sheet of stainless steel of SUS304 of JIS G4304, "aluminum" is a sheet of aluminum of alloy symbol A5052 of JIS H4000, and "copper" is an alloy of JIS H3100. It means that a copper sheet of symbol C1100 is used. The dimensions of the substrate sheet were the same as in Example 1.

(Comparative example 1)
Cellophane tape using a cellophane tape (made by Nichiban Co., Ltd., Cellotape (registered trademark) No. 405 (for industrial use), width 10 mm) and using the same stainless steel sheet as in Example 2 as a substrate sheet Were attached to a stainless steel sheet to prepare a laminate of cellophane tape and a stainless steel sheet. The resulting laminate was used for the peel test. In Table 1, the column of the resin sheet was shown as "cellophane".

(Comparative example 2)
As a resin sheet, a PFA tape (made by Chuko Kasei Kogyo Co., Ltd., Chuko Flow adhesive tape, AFA-113A, width 25 mm) is used, and as a base sheet, a stainless steel sheet made of the same stainless steel as in Example 2 is used. It was stuck to a stainless steel sheet to prepare a laminate of PFA tape and stainless steel sheet. The resulting laminate was used for the peel test. In Table 1, the column of the resin sheet was shown as "PFA."

(Evaluation)
<Peeling test>
The 180-degree peel strength was measured using an autograph (AG-20 kNXPLUS, manufactured by Shimadzu Corporation) using the non-adhesive sheets and the laminates obtained in Examples and Comparative Examples. As a test condition, a tensile speed was set to 20 mm / min, and an average value obtained four times was taken as a peel strength. The results are shown in Table 1.

From Table 1, in the example, since the peel strength is 3 N / mm or more, the pre-formed PTFE sheet and the base sheet are joined well, and the rice cooker, the heating cooker, and the conveyor for food conveyance are used. Even when used in food processing devices such as the body, it can be expected that the effect of PTFE can be sustained as compared to the prior art.

Claims (14)

  It is a laminated body in which a resin sheet whose main resin component is polytetrafluoroethylene and a substrate sheet are joined, and the peel strength between the resin sheet and the substrate sheet is 3 N / mm or more, not for food processing apparatus Adhesive sheet.   The non-adhesive sheet for a food processing apparatus according to claim 1, wherein the food processing apparatus is a rice cooker, a heating cooker, or a conveyor for food conveyance.   The non-adhesive sheet for food processing apparatus according to claim 1 or 2, wherein the resin sheet and the base sheet are joined via an adhesive.   The thickness of a resin sheet is 0.5 mm or more, The non-adhesive sheet for food processing apparatuses in any one of Claims 1-3.   The non-adhesive sheet for food processing apparatus according to any one of claims 1 to 4, wherein a fixing portion for fixing to the food processing apparatus is formed on the base sheet.   The adhesive is an adhesive fluorine-containing copolymer, The non-adhesive sheet for food processing apparatuses in any one of Claims 1-5.   The food processing apparatus provided so that the resin sheet side of the non-adhesive sheet in any one of Claims 1-6 might be a contact side of a foodstuff.   A rice cooker provided so that the resin sheet side of the non-adhesive sheet according to any one of claims 1 to 6 may be a side in contact with cooked rice.   The cooking-equipment provided so that the resin sheet side of the non-adhesive sheet in any one of Claims 1-6 might become the side which a foodstuff contacts, and / or the side which cooks a foodstuff.   The conveyance body for conveyors for foodstuffs conveyance provided so that the resin sheet side of the non-adhesive sheet in any one of Claims 1-6 might be a contact side of foodstuffs. A method for producing a non-adhesive sheet for a food processing apparatus according to claim 4, wherein
A method for producing a non-adhesive sheet, comprising the step of bonding a resin sheet having a thickness of 0.5 mm or more and a base sheet to a peel strength of 3 N / mm or more.   The non-adhesive sheet for food processing apparatus according to any one of claims 1 to 6 is installed on the food contact surface and / or the heating surface according to the shape, and at least a part of the sliding surface A method of manufacturing a food processing apparatus, comprising the steps of: The non-adhesive sheet for food processing apparatus according to any one of claims 1 to 6 is installed on the food contact surface and / or the heat cooking surface according to the shape, and the food contact surface and / or A method for surface modification of a food processing apparatus, comprising coating at least a part of a cooking surface and imparting non-stickiness to a food contact surface and / or a cooking surface. The conveyer for a conveyor for food conveyance which provided the non-adhesive sheet which consists of a layered product with which a resin sheet whose resin main ingredient is polytetrafluoroethylene was joined with a substrate sheet so that it might be in contact with food.