JP7033458B2 - Cutting board and manufacturing method of cutting board - Google Patents

Description

The present invention relates to a cutting board and a method for manufacturing the cutting board.

Conventionally, as a cutting board for cooking, a cutting board made of wood or a synthetic resin such as polyethylene is widely used. Both general household cutting boards and commercial cutting boards for the food service industry, school lunch centers, schools, nursery centers, etc. are used for cooking all kinds of ingredients such as meat, vegetables, and fish, and are sterilized due to the presence of odors and germs.・ Bactericidal treatment is required.

Conventionally, chemical sterilization has been the mainstream for such cutting board sterilization and sterilization treatments, but in recent years, due to measures such as O-157, which has become a social problem, high-temperature sterilization and sterilization treatments are shifting to. There is an increasing need for cutting boards that can withstand high temperatures caused by hot air and hot water.

However, among the cutting boards made of synthetic resin, the cutting board made entirely of low-density polyethylene (LDPE) cannot withstand high temperatures and is warped, distorted, and the like, which hinders its use.

In addition, cutting boards made of low-density polyethylene have the problem that shallow cuts are easily made by kitchen knives, which causes sagging, fluffing, and shaving, which causes contamination with food and dents on the surface. .. On the other hand, a polypropylene cutting board, which is harder than low-density polyethylene, has been proposed. Since it causes a feeling of fatigue, it is not particularly suitable as a cutting board for business use, and the fact is that it is mainly used only for outdoor applications.

It is mainly composed of high-density polyethylene (HDPE) for the purpose of solving these problems, that is, to make a cutting board that does not cause deformation such as warpage even by high temperature sterilization / sterilization treatment and has a good usability. A polyethylene cutting board made of a laminated body in which a layer mainly composed of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) is laminated as a surface layer on both sides of the intermediate layer has been proposed (for example). , Patent Document 1).

However, if this polyethylene (resin) cutting board is applied to a large-sized cutting board used in the food service industry, school lunch centers, nursery centers, etc., it will be heavy and will hinder high-temperature sterilization and sterilization work. I have a problem of sterilization. Further, even for a small cutting board mainly used for general household use, a housewife who is inferior in strength wants to develop a lighter cutting board.

Japanese Unexamined Patent Publication No. 2004-215718

An object of the present invention is to provide a resin cutting board which is not deformed by high temperature sterilization / sterilization treatment and has a good usability while reducing the weight, and a manufacturing method for manufacturing such a cutting board. To do.

Such an object is achieved by the present invention described in the following (1) to ( 9 ).
(1) A foamed layer made of a porous body containing a polyethylene-based resin containing at least one of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE).
Two surface layers containing a polyethylene-based resin containing low-density polyethylene (LDPE) laminated on both sides of the foam layer as the outermost layer as a main material, respectively.
Two protective layers containing a polyolefin resin as a main material are provided between the foam layer and the two surface layers, respectively.
In the protective layer, the polyolefin-based resin is low-density polyethylene (LDPE) or a mixture of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) or linear low-density polyethylene (LLDPE).
The content of the low density polyethylene (LDPE) in the protective layer is higher than the content of the low density polyethylene (LDPE) in the surface layer.
The protective layer is a cutting board whose hardness is lower than the hardness of the surface layer.

(2) The cutting board according to (1) above, wherein the foam layer is the cutting board according to (1) above, wherein when the foam layer is composed of a dense body, the hardness of the dense body is higher than the hardness of the surface layer.

(3) In the foam layer, at least one of the high-density polyethylene (HDPE) and the linear low-density polyethylene (LLDPE) has a content of 10% by mass or more and 90% by mass or less (the above). The cutting board according to 1) or (2).

(4) The cutting board according to any one of (1) to (3) above, wherein the low-density polyethylene (LDPE) in the surface layer has a content of 60% by mass or more and 95% by mass or less.

( 5 ) When the total thickness of the cutting board is (T) [mm] and the thickness of each surface layer is (t1) [mm], the thickness of the two surface layers with respect to the total thickness (T) of the cutting board. The cutting board according to any one of (1) to ( 4 ) above, wherein the ratio of (t1) satisfies the relationship of 0.1 ≦ t1 / T ≦ 0.3.

( 6 ) When the total thickness of the cutting board is (T) [mm] and the thickness of each protective layer is (t2) [mm], the thickness of the two protective layers with respect to the total thickness (T) of the cutting board. The cutting board according to any one of (1) to ( 5 ) above, which satisfies the relationship that the ratio of (t2) is 0.01 ≦ t2 / T ≦ 0.1.

( 7 ) The cutting board according to any one of (1) to ( 6 ) above, wherein the foamed layer has a foaming ratio of 1.5 times or more and less than 5.0 times.

( 8 ) The cutting board according to any one of (1) to ( 7 ) above, wherein the average pore diameter of the pores in the foam layer is 0.03 mm or more and 0.3 mm or less.

( 9 ) The cutting board manufacturing method according to any one of (1) to ( 8 ) above.
A step of obtaining a laminate having the foam layer and the two protective layers laminated on both sides of the foam layer by using a coextrusion method.
A method for manufacturing a cutting board, which comprises a step of forming two surface layers on opposite sides of the foam layer of the two protective layers.

According to the present invention, since the foam layer that functions as the core material of the resin cutting board is composed of a porous body, the cutting board can be made lighter. Further, since this foam layer contains a polyethylene-based resin containing at least one of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE), it is warped even by high-temperature sterilization / sterilization treatment. It is possible to accurately suppress or prevent the occurrence of deformation of. Further, surface layers are laminated on both sides of the foam layer as outermost layers, and these surface layers have lower hardness than high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE). Since it contains a polyethylene-based resin containing low-density polyethylene (LDPE) as a main material, it is possible to improve the usability when using a kitchen knife. That is, a resin cutting board that does not cause deformation such as warpage even by high-temperature sterilization / sterilization treatment while being reduced in weight and has a good usability is realized.

Further, according to the present invention, after forming a laminate having a foam layer and a laminated protective layer on both sides of the foam layer by using a coextrusion method, the foam layers of the two protective layers are formed. A cutting board is manufactured by forming two surface layers on the opposite side of the surface layer, and the hardness of the protective layer is set lower than the hardness of the surface layer. Can be set to. Further, since the protective layer is interposed between the foam layer and the surface layer, it is possible to accurately suppress or prevent the unevenness formed on the surface of the foam layer from propagating to the surface layer. The surface of the surface layer opposite to the foam layer, that is, the surface of the cutting board on which the food is placed, can be formed of a uniform flat surface.

It is a vertical sectional view which shows the embodiment of the cutting board of this invention. It is a vertical sectional view for demonstrating the manufacturing method for manufacturing the cutting board shown in FIG. 1.

Hereinafter, the cutting board of the present invention and the method for manufacturing the cutting board will be described in detail based on the preferred embodiments shown in the accompanying drawings.

<Cutting board 100>
FIG. 1 is a vertical sectional view showing an embodiment of the cutting board of the present invention. In the following description, the upper side in FIG. 1 is referred to as "upper" and the lower side is referred to as "lower".

The cutting board 100 of the present invention is a foamed layer 10 (intermediate) made of a porous body, which contains a polyethylene-based resin containing at least one of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE). Layers) and two surface layers 31 and 32, each of which is laminated on both sides of the foamed layer 10 and contains a polyethylene resin containing low density polyethylene (LDPE) as a main material, and foamed. Two protective layers 21 and 22 containing a polyethylene-based resin as a main material are interposed between the layer 10 and the two surface layers 31 and 32, respectively, and the protective layers 21 and 22 have their hardness. Is lower than the hardness of the surface layers 31 and 32.

By providing the cutting board 100 with such a configuration, the foam layer 10 that functions as a core material is composed of a porous body, so that the cutting board 100 is reduced in weight. Further, since the foamed layer 10 contains a polyethylene-based resin containing at least one of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE), for example, high-temperature sterilization at 100 ° C. or higher is performed. -The sterilization process can also accurately suppress or prevent the occurrence of (heat) deformation such as warpage and distortion.

Further, surface layers 31 and 32 are laminated as outermost layers on both sides of the foam layer 10, respectively, and these surface layers 31 and 32 are the high-density polyethylene (HDPE) contained in the foam layer 10 and the direct layer. Since it contains a polyethylene-based resin containing low-density polyethylene (LDPE), which has a lower hardness than chain low-density polyethylene (LLDPE), as the main material, it should have a good usability when using a kitchen knife. Can be done.

Further, the method for manufacturing the cutting board 100 of the present invention is a laminated body provided with a foam layer 10 and two protective layers 21 and 22 laminated on both sides of the foam layer 10 by a coextrusion method, respectively. It is characterized by having a step of forming the two surface layers 31 and 32, respectively, on the opposite side of the foam layer 10 of the two protective layers 21 and 22. According to such a manufacturing method, after forming a laminate having the foam layer 10 and the laminated protective layers 21 and 22 on both side surfaces of the foam layer 10 by using a coextrusion method, 2 A cutting board 100 is manufactured by forming two surface layers 31 and 32 on the opposite sides of the protective layers 21 and 22 from the foam layer 10, respectively, and the hardness of the protective layers 21 and 22 is the surface layers 31 and 32. Since the hardness is set lower than that of the above, the expansion ratio of the foam layer 10 can be easily set within a target range. Further, since the protective layers 21 and 22 are interposed between the foam layer 10 and the surface layers 31 and 32, the unevenness caused by the pores formed on the surface of the foam layer 10 is formed on the surface layer 31. It is possible to accurately suppress or prevent propagation to 32. Therefore, the surface of the surface layers 31 and 32 opposite to the foam layer 10, that is, the surface of the cutting board 100 on which the food is placed can be formed of a uniform flat surface.

Hereinafter, the foam layer 10 provided in the cutting board 100, two surface layers 31 and 32 laminated as outermost layers on both side surfaces of the foam layer 10, and the foam layer 10 and two surface layers 31 and 32, respectively. The two protective layers 21 and 22, respectively inserted between them, will be described in detail.

In the present specification, the polyethylene-based resin is low-density polyethylene (hereinafter, may be referred to as “LDPE”) or linear low-density polyethylene (hereinafter, may be referred to as “LLDPE”). And high-density polyethylene (hereinafter, also referred to as "HDPE"), which is a single or mixed polyethylene containing one or more, and LDPE is usually 0.91 or more and 0.94 [unit]. : G / cm ² ] or less, LLDPE is usually 0.91 or more and 0.94 or less, and HDPE is usually 0.94 or more and 0.97 or less. Further, the layers 10, 21, 22, 31, 32 containing this polyethylene-based resin as an essential or arbitrary constituent material may be used as a resin other than the polyethylene-based resin, an antibacterial agent, a colorant, etc., unless contrary to the object of the present invention. It may contain other components.

<Foam layer 10>
The foam layer 10 is provided as an intermediate layer in the cutting board 100 made of a multilayer body (laminated body), and has a function as a core material.

In the present invention, the foamed layer 10 contains a polyethylene-based resin containing at least one of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE). As described above, HDPE and LLDPE have a higher density than the density of LDPE, and when a dense body composed of at least one of them is formed, the dense substance composed of LDPE is formed. It is higher than the hardness of (for example, surface layers 31, 32). Therefore, by using the foam layer 10 containing HDPE and LLDPE as a core material, it is possible to accurately determine that (heat) deformation such as warpage and strain occurs even by high temperature sterilization / sterilization treatment at 100 ° C. or higher, for example. Can be suppressed or prevented.

Further, the polyethylene-based resin contained in the foam layer 10 may be either HDPE or LLDPE, but HDPE having a high density is preferable. Thereby, the above-mentioned effect can be exerted more remarkably.

Further, in the foam layer 10, the content of at least one of HDPE and LLDPE is preferably 10% by mass or more and 90% by mass or less, and more preferably 30% by mass or more and 80% by mass or less. It is more preferably 40% by mass or more and 70% by mass or less. Thereby, the above-mentioned effect can be exerted more remarkably. If the content of HDPE and / or LLDPE in the foam layer 10 is less than 10% by mass, the effect of suppressing thermal deformation of the cutting board 100 during high-temperature sterilization / sterilization treatment is ineffective depending on the blending ratio of HDPE and LLDPE. May be sufficient. On the other hand, if the content of HDPE and / or LLDPE in the foam layer 10 exceeds 90% by mass, the formability of the polyethylene-based resin deteriorates when the cutting board 100 is manufactured, and the cutting board as a molded product during extrusion molding. Since warpage is likely to occur in 100, productivity may decrease, which is not preferable.

Further, the foam layer 10 may contain at least one other constituent material of HDPE and LLDPE as long as it does not contradict the object of the present invention, and specifically, it is low as a polyethylene-based resin. Examples thereof include density polyethylene (LDPE), resins other than polyethylene-based resins, antibacterial agents, colorants and the like, and LDPE is particularly preferable. As a result, the hardness of the foam layer 10 can be easily set within a target range, so that the foam layer 10 can surely exhibit its function as a core material.

Examples of the resin other than the polyethylene-based resin include a thermoplastic resin excluding the polyethylene-based resin and a thermosetting resin, and one or more of these can be mixed and used.

Examples of the thermoplastic resin include polypropylene, polyolefin resins excluding ethylene resins such as ethylene-vinyl acetate copolymers, polyimide resins, polyimide resins such as polyetherimide resins, polyamide resins, and polyamideimide resins. Examples thereof include polyamide-based resins, acrylic-based resins, and phenoxy-based resins.

Examples of the thermosetting resin include epoxy resin, phenol resin, urea resin, melamine resin, polyester (unsaturated polyester) resin, polyimide resin, silicone resin, polyurethane resin and the like.

Further, in the present invention, the foam layer 10 is made of a porous body. By forming the foam layer 10 with a porous body in this way, the weight of the cutting board 100 can be reduced. Therefore, even if the cutting board 100 is applied to a large-sized cutting board used for business such as a restaurant industry, a school lunch center, a nursery center, etc., it is possible to accurately suppress the weight of the cutting board 100 from becoming unintentionally heavy. Therefore, the work of high temperature sterilization and sterilization can be carried out without causing any trouble.

The foamed layer 10 (porous body) may have a plurality of single pores in which a plurality of bead-shaped pores exist independently without communicating with each other, or the plurality of pores may be provided. It may be provided with a continuous hole (communication hole) that communicates three-dimensionally, but it is preferably provided with a single hole (independent hole). As a result, even if the foam layer 10 is made of a porous body, the decrease in hardness (strength) can be accurately suppressed. Further, by using a single hole, in the method for manufacturing a cutting board described later, when the foam layer 10 is formed, the single hole generated by the foaming agent can be stably maintained as compared with the continuous hole. Therefore, the foaming ratio of the foaming layer 10 can be set to a desired size relatively easily.

The average pore diameter (pore diameter) of the pores contained in the foam layer 10 is preferably 0.03 mm or more and 0.3 mm or less, and preferably 0.05 mm or more and 0.15 mm or less. More preferred.

Further, the foaming ratio of the foamed layer 10 (porous body) is preferably 1.5 times or more and less than 5.0 times, and more preferably 2.0 times or more and less than 3.0 times.

By setting the pore diameter of the pores contained in the foam layer 10 and the expansion ratio of the foam layer 10 within the above ranges, even if the foam layer 10 is made of a porous body, the strength thereof can be accurately reduced. It can be suppressed. Further, in the porous body, it is possible to prevent the pores from being connected to each other and to easily form a single pore.

As described above, by forming the foam layer 10 with a porous body, the weight of the foam layer 10 can be reduced, but on the contrary, there is a concern that the strength of the foam layer 10 is reduced. In the above, it is assumed that at least one of HDPE and LLDPE is contained as a constituent material of the foam layer 10. Therefore, even if the foamed layer 10 is made of a porous body, the decrease in strength thereof can be accurately suppressed, and the foamed layer 10 can exhibit excellent hardness.

The thickness of the foam layer 10 is preferably set to about 5.0 mm or more and 30.0 mm or less, more preferably 8.0 mm or more and 20.0 mm or less. By setting the thickness of the foam layer 10 within such a range, the foam layer 10 can function as a core material to reduce the weight of the cutting board 100, and the cutting board 100 can be sterilized by high temperature sterilization. It is possible to accurately suppress or prevent deformation such as warpage.

Further, when the foam layer 10 is composed of a dense body instead of a porous body, it is preferable that the plasmid D hardness specified in JIS K7215 of the dense body is 53 or more and 62 or less. As a result, the foam layer 10 made of this dense body as a porous body can surely exert its function as a core material.

<Surface layers 31, 32>
The surface layers 31 and 32 are provided as the outermost layer in the cutting board 100 composed of the multilayer body (laminated body), that is, the surface layer 31 (first surface layer) and the surface layer 32 (second surface layer) are provided. They are provided as the outermost layers on the upper surface (one surface) side of the foam layer 10 and the lower surface (the other surface) side of the foam layer 10, respectively, and exhibit a function for improving the usability when using a kitchen knife. do.

In the present invention, these two surface layers 31 and 32 contain a polyethylene-based resin containing low-density polyethylene (LDPE) as a main material. As described above, the density of LDPE is lower than that of HDPE and LLDPE, and the hardness of the dense body (surface layers 31, 32) composed of LDPE is at least one of HDPE and LLDPE. It is lower than the hardness of the constituent dense body. Therefore, by using the surface layers 31 and 32 containing such LDPE as the outermost layer, it is possible to improve the usability when using a kitchen knife. That is, since the cutting edge of the kitchen knife easily bites into the surface of the cutting board, excellent sharpness can be obtained, and further, since the cutting edge of the kitchen knife touches the surface of the cutting board is soft, an excellent usability can be obtained. Therefore, even if it is used for a long time, there is little feeling of fatigue.

Further, in the surface layers 31 and 32, the content of LDPE is preferably 60% by mass or more and 95% by mass or less, and more preferably 70% by mass or more and 85% by mass or less. As a result, it is possible to improve the usability when using a kitchen knife, and it is possible to impart appropriate hardness and heat-resistant meltability to the surface of the cutting board 100, so that surface damage such as sasakure and high-temperature sterilization / sterilization can be performed. It is possible to accurately suppress or prevent the surface of the cutting board 100 from being thermally melted during the treatment. When the content of LDPE in the surface layers 31 and 32 is less than 60% by mass, the hardness of the surface layers 31 and 32 becomes too high depending on the types of other constituent materials contained in the surface layers 31 and 32. It is not preferable because it may reduce the usability when using a kitchen knife. On the other hand, when the content of LDPE in the surface layers 31 and 32 exceeds 95% by mass, the heat resistance of the surface layers 31 and 32 is insufficient depending on the types of other constituent materials contained in the surface layers 31 and 32. It may melt at 100 ° C.

Further, the surface layers 31 and 32 may contain other constituent materials of LDPE as long as they do not contradict the object of the present invention, and specifically, at least of HDPE and LLDPE as polyethylene-based resins. One type, resins other than polyethylene-based resins, antibacterial agents, colorants and other other components are mentioned, and HDPE is particularly preferable. As a result, the hardness of the surface layers 31 and 32 can be easily set within a target range, so that the surface layers 31 and 32 can surely exhibit the function as the outermost layer.

As the resin other than the polyethylene-based resin, the same resin as mentioned in the foam layer 10 can be used.

Further, when the total thickness of the cutting board 100 is (T) [mm] and the respective thicknesses of the surface layers 31 and 32 are (t1) [mm], these surface layers 31 with respect to the total thickness (T) of the cutting board 100. , The ratio of the thickness (t1) of 32 preferably satisfies the relationship of 0.1 ≦ t1 / T ≦ 0.3, more preferably 0.15 ≦ t1 / T ≦ 0.25.

Specifically, the thicknesses of the surface layers 31 and 32 are preferably set to about 1.5 mm or more and 9.0 mm or less, and more preferably about 2.25 mm or more and 7.5 mm or less, respectively.

By setting the relationship of t1 / T and the thickness of the surface layers 31 and 32 within the above range, the surface layers 31 and 32 can more reliably exert the function as the outermost layer, and when a kitchen knife is used. It is possible to surely improve the usability of.

Further, the surface layers 31 and 32 preferably have a durometer D hardness specified in JIS K7215 of 48 or more and 55 or less, and more preferably 49 or more and 53 or less. As a result, the surface layers 31 and 32 can surely exert the function as the outermost layer. Therefore, it is possible to further improve the usability when using a kitchen knife, and more accurately suppress surface damage such as sasakure and heat melting of the surface of the cutting board 100 during high temperature sterilization / sterilization treatment. Can be prevented.

<Protective layers 21, 22>
The protective layers 21 and 22 are provided between the foam layer 10 and the two surface layers 31 and 32, respectively, in the cutting board 100 composed of the multilayer body (laminated body), that is, the protective layer 21 is provided. The (first protective layer) and the protective layer 22 (second protective layer) are between the foam layer 10 and the surface layer 31 (first surface layer), and between the foam layer 10 and the surface layer 32 (second surface, respectively). By being provided so as to be interposed between the layer) and covering the foam layer 10 in the method of manufacturing a cutting board 100 described later, the foaming ratio of the foam layer 10 is set within a target range, and the foam layer 10 is set to a target range. It has a function of suppressing or preventing the unevenness formed on the surface of the foam layer 10 from propagating to the surface layers 31 and 32.

In the present invention, these two protective layers 21 and 22 contain a polyolefin-based resin as a main material, and the hardness thereof is set to be lower than the hardness of the surface layers 31 and 32. As described above, by making the protective layers 21 and 22 contain the polyolefin resin as the main material, the hardness of the protective layers 21 and 22 can be easily set lower than the hardness of the surface layers 31 and 32. Can be done.

Examples of the polyolefin resin include ethylene, propylene, 1-butene, isobutene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene and 3-methyl-1-pentene. Monopolymers of α-olefins such as 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-icosen, Examples thereof include a copolymer of at least two types of α-olefins, a copolymer of α-olefins and other monomers, and a mixture of two or more types of these polyolefin resins.

The other monomer can be copolymerized with α-olefin, and for example, unsaturated carboxylic acid such as acrylic acid and methacrylic acid, unsaturated carboxylic acid such as acrylic acid ester and methacrylic acid ester. Acid esters, polybasic unsaturated carboxylic acids such as maleic acid, acid anhydrides of polybasic unsaturated carboxylic acids, 1,3-butadiene, isoprene, 1,3-pentadiene, 1,3-hexadiene, dicyclo Conjugate diene such as pentadiene, 1,4-hexadiene, 1,9-decadien, cyclooctadiene, norbornadiene, methylenenorbornene, etilidennorbornene, non-conjugated diene such as 7-methyl-1,6-octadien and the like can be mentioned. ..

Specific examples of such polyolefin-based resins include various polyethylenes such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE), isotactic polypropylene, and syndiotactic polypropylene. , Block polypropylene, various polypropylenes such as random polypropylene, ethylene-vinyl acetate copolymer (EVA), polyethylene-methyl methacrylate copolymer (EMMA), ethylene-styrene copolymer, one or more. Can be mentioned. Further, the polyolefin resin is particularly one containing low density polyethylene (LDPE) alone, or a mixture of low density polyethylene (LDPE) and high density polyethylene (HDPE) or linear low density polyethylene (LLDPE). Is preferable. Thereby, the hardness of the protective layers 21 and 22 can be set more reliably than the hardness of the surface layers 31 and 32.

When the polyolefin resin contains LDPE alone or is a mixture of LDPE and HDPE or LLDPE, the content of LDPE in the protective layers 21 and 22 is the content of LDPE in the surface layers 31 and 32. The amount is higher than the amount, whereby the hardness of the protective layers 21 and 22 is set lower than the hardness of the surface layers 31 and 32. Specifically, the content of LDPE in the protective layers 21 and 22 in this case is preferably 70% by mass or more and 100% by mass or less, and more preferably 75% by mass or more and 95% by mass or less. Thereby, in the method for manufacturing the cutting board 100 described later, the foaming ratio of the foamed layer 10 can be surely set within the target range, and the unevenness formed on the surface of the foamed layer 10 is formed on the surface layer 31. Propagation to 32 can be reliably suppressed or prevented.

Further, the protective layers 21 and 22 may contain other constituent materials of the polyolefin-based resin as long as they do not contradict the object of the present invention, and specifically, a resin other than the polyolefin-based resin, an antibacterial agent, and the like. Other components such as colorants can be mentioned.

Examples of the resin other than the polyolefin-based resin include the thermoplastic resin excluding the polyolefin-based resin mentioned in the foam layer 10 and the thermosetting resin.

By making the protective layers 21 and 22 contain such a polyolefin resin as a main material, it is relatively easy to make the protective layers 21 and 22 having a hardness lower than the hardness of the surface layers 31 and 32. Can be set to.

Specifically, the durometer D hardness specified in JIS K7215 of the protective layers 21 and 22 is preferably 20 or more and 49 or less, and more preferably 30 or more and 48 or less. Thereby, in the method for manufacturing the cutting board 100 described later, the foaming ratio of the foamed layer 10 can be surely set in the target range, and the unevenness formed on the surface of the foamed layer 10 is formed on the surface layers 31, 32. Can be reliably suppressed or prevented from propagating to.

When the total thickness of the cutting board 100 is (T) [mm] and the respective thicknesses of the protective layers 21 and 22 are (t2) [mm], the protective layer 21 with respect to the total thickness (T) of the cutting board 100. , 22 has a thickness (t2) ratio of preferably 0.01 ≦ t2 / T ≦ 0.1, more preferably 0.02 ≦ t2 / T ≦ 0.05.

Specifically, the thicknesses of the protective layers 21 and 22 are preferably set to about 0.2 mm or more and 2.0 mm or less, and more preferably 0.4 mm or more and 1.0 mm or less, respectively.

By setting the relationship of t2 / T and the thickness of the protective layers 21 and 22 within the above range, the foaming ratio of the foaming layer 10 is surely set within the target range in the method for manufacturing the cutting board 100 described later. In addition, it is possible to reliably suppress or prevent the unevenness formed on the surface of the foam layer 10 from propagating to the surface layers 31 and 32.

The cutting board 100 as described above may have the same size, thickness, shape, etc. as the conventional cutting board, and may be applied to any use such as commercial use, general household use, outdoor use, and is not particularly limited. However, since the foam layer 10 is made of a porous body, the weight is reduced, and even if it is applied to a large-sized cutting board used for business purposes, the weight of the cutting board 100 is accurately suppressed from becoming unintentionally heavy. Therefore, it is preferably applied to commercial products.

The cutting board 100 having such a configuration is manufactured by using, for example, the manufacturing method of the cutting board 100 to which the extrusion method is applied (the cutting board manufacturing method of the present invention) as shown below.

(Manufacturing method of cutting board 100)
FIG. 2 is a vertical cross-sectional view for explaining a manufacturing method for manufacturing the cutting board shown in FIG. In the following description, the upper side in FIG. 2 is referred to as "upper" and the lower side is referred to as "lower".

The method for manufacturing a cutting board 100 of the present invention is a step of obtaining a laminated body provided with a foam layer 10 and two protective layers 21 and 22 laminated on both sides of the foam layer 10 by a coextrusion method, respectively. And the steps of forming the two surface layers 31 and 32 on the opposite sides of the two protective layers 21 and 22 from the foam layer 10, respectively.

Hereinafter, each step for manufacturing the cutting board 100 will be described in detail.
[1] First, a co-extruded method is used to obtain a laminated body including the foamed layer 10 and two protective layers 21 and 22 laminated on both sides of the foamed layer 10, respectively.

In this step [1], the mixture (A) containing the constituent material and the foaming agent constituting the foam layer 10 described above and the constituent material (B) constituting the protective layers 21 and 22 are composed of the constituent material (B). ), The mixture (A) and the constituent material (B) are laminated in this order, and the molten resin in a molten state or a softened state is extruded from the opening of the T-die provided in the extruder. As a result, the molten sheet in the molten state or the softened state, which is a strip-shaped sheet, is continuously sent out, and then both sides of the molten sheet are flattened and cooled to be placed on both sides of the foam layer 10. A laminated body in which the protective layers 21 and 22 are laminated is obtained, respectively.

At this time, due to the action of the foaming agent contained in the mixture (A), the mixture (A) becomes a porous body in the molten sheet in the molten state or the softened state. Then, since the constituent materials (B) constituting the protective layers 21 and 22 having a hardness lower than the hardness of the surface layers 31 and 32, respectively, are laminated (coated) on both surfaces of the mixture (A). It is possible to accurately suppress or prevent the pores formed in the mixture (A) from bursting and the foaming ratio in the mixture (A) from falling below the target range.

Here, both sides of the mixture (A) made of a porous body (foam) are covered with the constituent material (B) constituting the protective layers 21 and 22 having a hardness lower than the hardness of the surface layers 31 and 32. The reason is as follows. That is, the porous body made of the mixture (A) has a small heat capacity per unit volume due to its light specific gravity. As described above, when the heat capacity of the porous body is small, in this step, a laminated body provided with a foam layer 10 and two protective layers 21 and 22 extruded by a coextrusion method is obtained in the next step [2]. When forming the two surface layers 31 and 32, the required heat may be insufficient, and as a result, sufficient adhesion between the protective layers 21 and 22 and the surface layers 31 and 32 may not be obtained. On the other hand, both sides of the mixture (A) are covered with the constituent material (B) constituting the protective layers 21 and 22 having a hardness lower than the hardness of the surface layers 31 and 32, in other words, a coextrusion method. Is used to protect the protective layers 21 and 22 containing a high content of a polyolefin resin such as low density polyethylene (LDPE), which has an excellent affinity for both sides of the foamed layer 10. The cutting board 100 can be obtained as a laminated body having excellent adhesion between the layers 21 and 22 and the surface layers 31 and 32.

The method for obtaining the mixture (A) by incorporating a foaming agent into the resin composition constituting the foam layer 10 is not particularly limited, but for example, A) a heat-decomposable foaming agent such as sodium bicarbonate is used as the foam layer. A method of adding to the constituent material of the foam layer 10 (foaming agent decomposition method), B) a method of bringing the gas into contact with the constituent material of the foamed layer 10 in a liquid phase state (liquid phase impregnation method) in an atmosphere of critical pressure or higher. C) A method of bringing the gas into contact with the constituent material of the foamed layer 10 in a vapor phase state (gas phase impregnation method) under a high pressure atmosphere of less than the critical pressure can be mentioned. Among them, the vapor phase impregnation method is particularly effective. C) is preferable. According to the vapor phase impregnation method C), the content of the foaming agent in the constituent material of the foam layer 10 can be easily increased. Therefore, the obtained foamed layer 10 can have a high foaming ratio (high pore ratio), and the bubble size in the foamed layer 10 can be made more uniform. Further, as compared with the liquid phase impregnation method B), equipment such as a pressure resistance device and a cooling device can be simplified, and the cost can be suppressed, which is also preferable.

The foaming agent is not particularly limited, and generally used gas can be used. Specifically, for example, air, carbon dioxide gas, nitrogen gas, oxygen gas, argon gas, helium gas and the like can be used. Inorganic gas, fluorocarbons such as trichlorofluoromethane (R11), dichlorodifluoromethane (R12), chlorodifluoromethane (R22), difluoroethane (R152a), saturated hydrocarbons such as propane, n-butane, i-butane, n-pentane and the like. Ethers such as hydrogen, dimethyl ether, diethyl ether, methyl ethyl ether, isopropyl ether, ketones such as dimethyl ketone, methyl ethyl ketone and diethyl ketone, alcohols such as methanol, ethanol and propyl alcohol, oleic acid methyl ester, oleate ethyl ester, and oleic acid. Examples thereof include carboxylic acid esters such as propyl ester, chlorinated hydrocarbons such as methyl chloride and ethyl chloride, and one or more of these can be used in combination.

Further, it is preferable to use a foaming agent in which these gases are enclosed in acrylic beads. Thereby, the foam layer 10 can be relatively easily formed as having a single hole (independent hole).

Among these, an inorganic gas is preferable. From the viewpoint of flame retardancy, the foaming agent is preferably non-flammable or non-flammable, and from the viewpoint of gas safety, an inorganic gas is preferably used.

Further, among the inorganic gases, carbon dioxide gas is preferable. Carbon dioxide gas is preferably used because it is easy to handle and has excellent solubility in the constituent materials of the foam layer 10.

When carbon dioxide gas is used, the impregnation amount in the mixture (A) is preferably 3 wt% or more and 13 wt% or less, and 3.5 wt% or more and 10 wt% or less with respect to the constituent material of the foam layer 10. It is more preferable to have.

If the amount of carbon dioxide impregnated is less than the lower limit, it is difficult to achieve a high foaming ratio, the bubble size tends to vary, and the foaming ratio tends to vary widely among the pores. Further, when the content of carbon dioxide gas exceeds the upper limit value, a tendency of hyperfoaming is exhibited, so that the porosity for forming a single pore may decrease.

The conditions in the gas phase impregnation method C) are not particularly limited, but the atmospheric pressure is preferably 0.5 MPa or more and 6.0 MPa or less, and more preferably 2.0 MPa or more and 4.0 MPa or less. The atmospheric temperature is preferably 5 ° C. or higher and 30 ° C. or lower, and more preferably 7 ° C. or higher and 15 ° C. or lower. By setting the atmospheric pressure and atmospheric temperature conditions within the above ranges, gas dissolution in the resin composition can be facilitated more efficiently.

Further, the foaming method in the gas phase impregnation method C) is not particularly limited, but for example, a method of expanding the gas dissolved in the constituent material of the foam layer 10 by opening the foam under a low pressure atmosphere from a high pressure condition. Examples thereof include a method of heating the mixture to expand the gas dissolved in the constituent material of the foam layer 10, and these can be used alone or in combination.

[2] Next, the two surface layers 31 and 32 are formed on the opposite sides of the two protective layers 21 and 22 from the foam layer 10 provided in the laminate obtained in the step [1], respectively.

In this step [2], the constituent materials constituting the surface layers 31 and 32 on the opposite sides of the two protective layers 21 and 22 from the foam layer 10 provided in the laminate obtained in the step [1], respectively. (C) is adjusted to a sheet shape in advance and is sent out as a sheet-shaped surface layer resin. As a result, the sheet-shaped surface layer resin is continuously fed out to the two protective layers 21 and 22 provided in the laminated body formed of the strip-shaped sheet, and further, the surface layer under heating at the time of this feeding out. After crimping the resin, the surface of the surface layer resin is flattened and cooled to obtain a cutting board 100 on which the surface layers 31 and 32 are laminated on the protective layers 21 and 22, respectively.

At this time, the protective layers 21 and 22 are formed on both sides of the foam layer 10 in the laminated body, respectively. Here, in the step [1], when the laminate provided with the foam layer 10 is formed by using the coextrusion method, the porous body (foam) becomes rice cake in a part of the resin pool extruded from the T die. As a result, unevenness is inevitably formed on the surface of the foam layer 10. By providing the protective layers 21 and 22 on both sides of the foam layer 10 on which such unevenness is formed, it is possible to accurately suppress or prevent the unevenness from propagating to the surface layers 31 and 32, respectively. .. Therefore, the surface of the surface layers 31 and 32 opposite to the foam layer 10, that is, the surface of the cutting board 100 on which the food is placed can be formed of a uniform flat surface.

Through the above steps, the foam layer 10 made of a porous body, the two surface layers 31 and 32 laminated on both sides of the foam layer 10 as the outermost layers, and the foam layer 10 A cutting board 100 having two protective layers 21 and 22 interposed between the two surface layers 31 and 32, respectively, is manufactured.

The cutting board of the present invention and the method for manufacturing the cutting board have been described above, but the present invention is not limited to this, and each layer constituting the cutting board has an arbitrary configuration capable of exhibiting the same function. Can be replaced with. Further, any component may be added.

Further, the cutting board may have a bonding layer (adhesive layer) or the like interposed between the foam layer and the protective layer, or a bonding layer (adhesive layer) or the like between the protective layer and the surface layer. May intervene.

Further, one or two or more steps of arbitrary purpose may be added to the cutting board manufacturing method.

Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited thereto.

1. 1. Manufacture of cutting board [Example 1]
[1] First, 50 parts by mass of high-density polyethylene (HDPE; manufactured by Keiyo Polyethylene, "B5203"), 50 parts by mass of low-density polyethylene (LDPE; manufactured by Ube Maruzen Polyethylene, "F222F"), and 10 mass. A material for forming a foam layer was prepared by stirring and mixing the polyethylene gas-containing foam master batch (Sankyo Kasei Co., Ltd., “Cellmic 5858”, generated gas amount of about 35 ml / g).

Further, 5 parts by mass of high-density polyethylene (HDPE; manufactured by Keiyo Polyethylene, “B5203”) and 95 parts by mass of low-density polyethylene (LDPE; manufactured by Ube-Maruzen Polyethylene, “F222F”) are stirred and mixed. Therefore, it was prepared as a material for forming a protective layer.

Further, 17 parts by mass of high-density polyethylene (HDPE; manufactured by Keiyo Polyethylene, “B5203”) and 83 parts by mass of low-density polyethylene (LDPE; manufactured by Ube-Maruzen Polyethylene, “F222F”) are stirred and mixed. Therefore, it was prepared as a material for forming a surface layer.

[2] Next, the prepared foam layer forming material and protective layer forming material are used as a protective layer forming material, and a foam layer forming material and a protective layer forming material, respectively, using a distributor. The dispersion, which is sequentially distributed in layers, is extruded from the opening of the T-die as a molten sheet, and then flattened and cooled to cover both the foam layer and the upper and lower surfaces of the foam layer. A laminate comprising a protective layer to be provided was obtained.

[3] Next, the surface layer forming material previously prepared in a sheet shape by the T-die extrusion method was heat-laminated on both the upper surface and the lower surface of the laminate obtained in the step [2]. Later, by flattening and cooling, surface layers were formed on the upper surface and the lower surface of the laminated body, respectively.

Through the above steps, a resin cutting board having a total thickness of 20 mm × a short side of 300 mm × a long side of 600 mm, a foam layer thickness of 11 mm, a protective layer thickness of 0.5 mm, and a surface layer thickness of 4 mm was produced. did.

[Examples 2 to 15]
The content of high density polyethylene (HDPE) and low density polyethylene (LDPE) contained in the protective layer forming material and the surface layer forming material, the content of the foam masterbatch contained in the foam layer forming material, and foaming. Cutting boards of Examples 2 to 15 were prepared in the same manner as in Example 1 except that at least one of the thicknesses of the layer, the protective layer and the surface layer was changed as shown in Table 1.

[Comparative Example 1]
A cutting board of Comparative Example 1 was produced in the same manner as in Example 1 above, except that the formation of the protective layer on the cutting board was omitted and the thickness of the foamed layer was changed as shown in Table 1.

[Comparative Example 2]
The same as in Example 1 above, except that the addition of the isobutane gas-containing foam masterbatch to the foam layer forming material was omitted and the thicknesses of the foam layer, the protective layer and the surface layer were changed as shown in Table 1. , The cutting board of Comparative Example 2 was prepared.

2. 2. Evaluation Method Using the cutting board (size: 20 mm × 300 mm × 600 mm) produced in each Example and each Comparative Example as a sample, evaluation was performed by the following method.

<Thickness uniformity>
It was evaluated whether the smoothness practical as a cutting board was obtained. The evaluation results are shown in Table 1.

[Evaluation result of thickness uniformity]
◎: Excellent thickness uniformity of the entire cutting board and can be used as a cutting board 〇: Can be used as a cutting board although there is some variation in the thickness uniformity of the entire cutting board ×: There is variation in the thickness of the cutting board Cannot be used as

<Bank stability>
When a laminate of a foam layer and a protective layer is produced by extrusion molding, it is a condition that the resin pool (bank) formed before the rolling roll is stable and a laminate having a uniform thickness is formed. The stability is shown in Table 1.

[Bank stability evaluation results]
◎: Excellent bank stability and stable production 〇: Bank stability is partially unstable, but production is possible ×: Bank is extremely unstable and cannot be produced

<Burning of the mold surface / lip residue>
When a laminate of a foam layer and a protective layer is produced by extrusion molding, if the foam layer comes into direct contact with the mold, burning and lip residue occur, and long running is not possible. Table 1 shows the state of burnt and lip shavings after several hours to 12 hours of production.

[Evaluation results of burnt mold surface and lip residue]
◎: No burning or lip residue even after 12 hours of operation 〇: Some burning or lip residue occurs after 12 hours of operation, but there is no problem with the quality of the laminate ×: Burning or lip residue occurs in a short time However, it is mixed in the product and the quality is significantly inferior.

<Laminate strength>
The surface layer was formed by so-called extrusion lamination as in the above step [3], and the fusion strength was evaluated by peeling and peeling with a knife.

[Evaluation result of laminate strength]
⊚: Extruded lamination does not show peeling, and stronger fusion strength can be obtained. 〇: Extruded lamination shows some peeling, but strong fusion strength can be obtained. ×: Extruded lamination provides fusion. Insufficient wearing strength and peeling

<Lightness>
The weight ratio at which lightness was recognized was 93% or less with respect to the conventional heat-resistant cutting board, and the cutting board size was 20 × 300 × 600 (mm) for comparative evaluation.

[Evaluation result of lightness]
◎: Compared to the conventional polyethylene cutting board, the weight is 75% or less and excellent weight reduction is recognized. 〇: Compared to the conventional polyethylene cutting board, the weight is more than 75% and 93% or less, and the weight reduction is recognized. ×: Compared to the conventional polyethylene cutting board, the weight exceeds 93% and quantification is hardly recognized.

<Heat-resistant warp>
When the cutting board is disinfected in a hot air storage, it is cooled after treatment at 90 ° C for 1 hour and placed on the surface plate with the convex surface facing up, and if it is warped, a gap is created between the cutting board and the surface plate. The interval was measured with a thickness gauge. The size of the cutting board was 20 × 300 × 600 (mm), and measurements were performed at two locations on the long side and two locations on the short side, for a total of four locations.

[Evaluation result of heat-resistant warp]
⊚: No warpage occurs with a gap of less than 0.8 mm from the flat surface 〇: Warpage occurs with a gap of 0.8 mm or more and less than 1.2 mm with the flat surface ×: Warpage occurs with a gap of 1.2 mm or more between the flat surface Occur

<Thermal melting of the surface>
It was stored in an air oven set at 110 ° C. for 1 hour, and whether or not thermal melting of the surface occurred was visually confirmed.

[Evaluation result of thermal melting on the surface]
⊚: No change in surface condition 〇: Slight melt deformation is seen in the surface condition ×: Clear melt deformation is seen in the surface condition

<Softness of the cutting board surface>
Using a cutting board, the blade contact of the kitchen knife and the sharpness of the ingredients were evaluated.

[Evaluation result of softness of cutting board surface]
◎: Excellent softness on the blade of the kitchen knife, especially excellent sharpness and usability 〇: Softness on the blade of the kitchen knife, excellent sharpness and usability ×: The blade contact of the kitchen knife Hard, dull, and uncomfortable to use

As shown in Table 1, in each embodiment, a cutting board is provided as an outermost layer on both sides of a foam layer containing at least one of HDPE and LLDPE and composed of a porous body. , Each of the two laminated surface layers containing LDPE as the main material and the two protective layers interspersed between the foam layer and the two surface layers, respectively, containing the polyolefin resin as the main material. By constructing this cutting board with a laminated body having ..

On the other hand, in each comparative example, the formation of the protective layer on the cutting board is omitted, or the addition of the foaming agent to the foam layer is omitted, and as a result, a cutting board that can withstand use can be manufactured. The results show that a cutting board that cannot be said to be impossible or that weight reduction has been achieved can be obtained.

10 Foam layer 21 Protective layer 22 Protective layer 31 Surface layer 32 Surface layer 100 Cutting board

Claims (9)

A foam layer made of a porous body containing a polyethylene-based resin containing at least one of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE).
Two surface layers containing a polyethylene-based resin containing low-density polyethylene (LDPE) laminated on both sides of the foam layer as the outermost layer as a main material, respectively.
Two protective layers containing a polyolefin resin as a main material are provided between the foam layer and the two surface layers, respectively.
In the protective layer, the polyolefin-based resin is low-density polyethylene (LDPE) or a mixture of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) or linear low-density polyethylene (LLDPE).
The content of the low density polyethylene (LDPE) in the protective layer is higher than the content of the low density polyethylene (LDPE) in the surface layer.
The protective layer is a cutting board whose hardness is lower than the hardness of the surface layer. The cutting board according to claim 1, wherein the foamed layer has a hardness higher than that of the surface layer when the foamed layer is composed of a dense body. Claim 1 or 2 in which the content of at least one of the high-density polyethylene (HDPE) and the linear low-density polyethylene (LLDPE) in the foam layer is 10% by mass or more and 90% by mass or less. Cutting board described in. The cutting board according to any one of claims 1 to 3, wherein the low-density polyethylene (LDPE) in the surface layer has a content of 60% by mass or more and 95% by mass or less. When the total thickness of the cutting board is (T) [mm] and the thickness of each surface layer is (t1) [mm], the thickness (t1) of the two surface layers with respect to the total thickness (T) of the cutting board. The cutting board according to any one of claims 1 to 4 , which satisfies the relationship that the ratio of is 0.1 ≦ t1 / T ≦ 0.3. When the total thickness of the cutting board is (T) [mm] and the thickness of each protective layer is (t2) [mm], the thickness (t2) of the two protective layers with respect to the total thickness (T) of the cutting board. The cutting board according to any one of claims 1 to 5 , which satisfies the relationship that the ratio of is 0.01 ≦ t2 / T ≦ 0.1. The cutting board according to any one of claims 1 to 6 , wherein the foamed layer has a foaming ratio of 1.5 times or more and less than 5.0 times. The cutting board according to any one of claims 1 to 7 , wherein the average pore diameter of the pores in the foam layer is 0.03 mm or more and 0.3 mm or less. The method for manufacturing a cutting board according to any one of claims 1 to 8 .
A step of obtaining a laminate having the foam layer and the two protective layers laminated on both sides of the foam layer by using a coextrusion method.
A method for manufacturing a cutting board, which comprises a step of forming two surface layers on opposite sides of the foam layer of the two protective layers.

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