JP2007075901A - Cutting mat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting mat, having excellent flexibility and elastic recovery nature of a scar, not deteriorating cutting performance for paper or the like in spite of continuous use, and not containing vinyl chloride. <P>SOLUTION: This cutting mat has a surface layer mainly composed of propylene resin composition, characterized in that it has a sea-island structure taking propylene and ethylene as essential components and containing a copolymer phase of propylene and another α-olefin having 8 or less carbon atoms in a matrix made of polymer component mainly composed of propylene and having a melting point peak temperature of 150 °C or more, wherein (1) xylene soluble part at a room temperature is 10 to 60 wt.%, (2) the content of α-olefin having 2 to 8 carbon atoms other than propylene in the xylene soluble part at a room temperature is 5 to 20 wt.%, and (3) the number average molecular weight of xylene soluble part at a room temperature ranges from 50,000 to 200,000. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cutting mat used as an underlay when cutting paper or the like with a cutter knife or the like, and more particularly, to a novel cutting mat that is less scratched by a cutter knife and scars are hardly noticeable due to elastic recovery. .

As cutting mats, soft vinyl chloride resin is excellent in moldability, flexibility, and elastic recovery of scars, so a soft vinyl chloride resin or a laminate of hard vinyl chloride resin and soft vinyl chloride resin has been widely used in the past. Have been used.
However, discussions on environmental issues that have been rapidly increasing in recent years have hit soft vinyl chloride resin directly from the suspicion of environmental hormones for plasticizers in soft vinyl chloride resin, and the fear of dioxin generation during disposal of vinyl chloride resin, The use of soft vinyl chloride resin has become difficult.

  On the other hand, ethylene-based resins such as copolymers of ethylene and vinyl acetate, methyl methacrylate, etc., low density polyethylene, linear low density polyethylene, or very low density polyethylene, are excellent in flexibility. As a material, the resilience of the scar is poor, and the scratched portion by the cutter knife remains open, making it difficult to reliably cut paper or the like. The thing using the polyolefin-type material is described in patent document 1 and patent document 2, for example.

In addition, homo-, random- or block-type general-purpose crystalline propylene resins are excellent in mechanical strength, but are inferior in flexibility and cutting properties. In order to improve flexibility and cutting properties, when the composition of the above-mentioned general-purpose crystalline propylene resin and ethylene or styrene-based elastomer is used, the composition ratio of the general-purpose crystalline propylene-based resin may be less than 50% by weight. Only the resiliency of the scar is improved to some extent, and the problems relating to molding processability or economy become significant.
JP 2000-211189 A JP 2002-127094 A

  The present invention has been made in view of the above circumstances, and is excellent in flexibility and resilience of scars, cutting properties such as paper do not deteriorate even when continuously used, and cutting without using vinyl chloride. The purpose is to provide a mat.

As a result of intensive studies to achieve the above object, the present inventors have found that a cutting mat having a surface layer mainly composed of a specific soft propylene-based resin achieves the above object, and has completed the present invention. .
That is, the present invention provides propylene and other α-carbon atoms having 8 or less carbon atoms, the main components of which are propylene and ethylene, in a matrix composed of a polymer component having a melting point peak temperature of 150 ° C. or higher. A propylene-based resin composition having a sea-island structure including a copolymer phase with olefin,
(1) The xylene solubles at room temperature is 10 to 60% by weight,
(2) The content of the α-olefin having 2 to 8 carbon atoms other than propylene in the xylene-soluble component at room temperature is 5 to 20% by weight,
(3) Provided is a cutting mat having a surface layer mainly composed of the propylene resin composition, wherein the number average molecular weight of xylene solubles at room temperature is in the range of 50,000 to 200,000. .

In the cutting mat of the present invention, the propylene-based resin composition is preferably,
(1) The xylene solubles at room temperature is 20 to 50% by weight,
(2) The content of the α-olefin having 2 to 8 carbon atoms other than propylene in the xylene-soluble component at room temperature is 10 to 18% by weight.

  In the cutting mat of the present invention, the propylene-based resin composition is preferably a polymer component having a melting point peak temperature of 150 ° C. or higher mainly composed of 10 to 60% by weight of propylene with respect to the whole composition, A copolymer of propylene and another α-olefin having 8 or less carbon atoms, containing 40 to 90% by weight of propylene and ethylene as essential components is included.

  In the cutting mat of the present invention, a copolymer phase of propylene and another α-olefin having 8 or less carbon atoms, which contains propylene and ethylene as essential components, has a sphere-equivalent average diameter, preferably 0. The size is about 1 to 1 μm, more preferably about 0.1 to 0.2 μm.

  The propylene-based resin composition used for the cutting mat of the present invention comprises a step of polymerizing a monomer mainly composed of propylene, ethylene, propylene, and other α-carbon atoms other than 8 if necessary. And a step of polymerizing a monomer containing olefin.

  The cutting mat of the present invention preferably comprises a base material layer mainly composed of crystalline polypropylene and a surface layer made of the propylene resin composition provided thereon. More preferably, the cutting mat of the present invention has a three-layer structure in which a surface layer made of the propylene-based resin composition is provided on both surfaces of the base material layer as described above.

  In the cutting mat of the present invention, the surface layer preferably has a thickness of 0.1 to 0.2 mm.

  The cutting mat of the present invention is excellent in flexibility and resiliency of scars, and even when continuously used, the cutting property of paper or the like does not deteriorate. Moreover, since it is not necessary to use the material containing vinyl chloride, it does not cause environmental problems.

  The cutting mat of the present invention has propylene and ethylene as essential components in a matrix composed of a polymer component having propylene as a main component and a melting point peak temperature of 150 ° C. or higher. It has a surface layer made of a propylene-based resin composition having a sea-island structure including a copolymer phase with an α-olefin, and the propylene-based resin composition has the following characteristics.

(1) The xylene-soluble content at room temperature is 10 to 60% by weight, preferably 20 to 50% by weight.
The matrix of the propylene-based resin composition used in the cutting mat of the present invention, which is composed of a polymer component having a melting point peak temperature of 150 ° C. or more mainly composed of propylene, is a crystalline polymer, and must contain propylene and ethylene. The copolymer phase of propylene and the other α-olefin having 8 or less carbon atoms, which is a component, is composed of an amorphous copolymer elastomer, and therefore xylene-soluble matter is substantially propylene. It corresponds to the majority of the copolymer phase of propylene and other α-olefins having 8 or less carbon atoms, which contain styrene and ethylene as essential components. Therefore, the propylene-based resin composition is substantially a polymer having a melting point peak temperature of 150 ° C. or higher mainly composed of 10 to 60% by weight, preferably 20 to 50% by weight, of propylene with respect to the whole composition. And a copolymer of propylene and another α-olefin having 8 or less carbon atoms, the essential component of which is 40 to 90% by weight, preferably 50 to 80% by weight of propylene and ethylene.

  When the xylene-soluble content at room temperature is less than 10% by weight, the flexibility of the resin composition and the resilience of the scar are poor, and when it exceeds 60% by weight, the mechanical strength of the resin composition is lowered. Here, “room temperature” usually refers to a temperature that is meant by the term “room temperature”, and specifically refers to a temperature of about 23 ° C.

(2) The content of the α-olefin having 8 or less carbon atoms other than propylene in the xylene-soluble component at room temperature is 5 to 20% by weight, preferably 10 to 18% by weight.
If the content of the α-olefin having 8 or less carbon atoms other than propylene in the xylene-soluble component at room temperature is less than 5% by weight, the flexibility of the resin composition and the elastic recovery of the scar are inferior, exceeding 20% by weight. And the mechanical strength of a resin composition falls.

(3) The number average molecular weight of the xylene solubles at room temperature is in the range of 50,000 to 200,000.
When the number average molecular weight of the xylene-soluble component at room temperature is less than 50,000, the mechanical strength of the resin composition decreases. When the number average molecular weight of the xylene-soluble component at room temperature exceeds 200,000, molding processing is performed. Inferior.

(4) The melting point peak temperature of the polymer component mainly composed of propylene is 150 ° C. or higher.
When the melting point peak temperature of the polymer component mainly composed of propylene is less than 150 ° C., sufficient rigidity of the propylene-based resin composition cannot be obtained.

  The propylene-based resin composition includes a step of polymerizing a monomer containing propylene as a main component and a step of polymerizing a monomer containing ethylene, propylene, and, if necessary, another α-olefin having 8 or less carbon atoms. Is produced by a multistage polymerization comprising:

  The “monomer having propylene as a main component” is a monomer containing 90% by weight or more of propylene, and the amount of propylene is preferably 95% by weight or more, and particularly preferably 100% by weight. As a monomer other than propylene, an α-olefin having 2 to 8 carbon atoms other than propylene is preferable, and ethylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 1 Examples include linear α-olefins such as hexene and 1-octene, and ethylene is particularly preferable.

  Examples of the α-olefin having 8 or less carbon atoms other than ethylene and propylene include 1-butene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 1 -Linear alpha olefins, such as octene, are mentioned. Moreover, unless the effect of this invention is inhibited, the other monomer may be contained.

  The propylene-based resin composition includes, for example, first-stage polymerization in which a monomer mainly composed of propylene is polymerized, and ethylene, propylene, and other α-olefin having 8 or less carbon atoms as necessary. It is produced by a two-stage polymerization including a second-stage polymerization for polymerizing monomers, but is not limited to this as long as the propylene-based resin composition is obtained, and can be produced in three or more stages. Good.

  The above polymerization is usually carried out in the presence of a catalyst, and the catalyst is not particularly limited, but a catalyst containing an organoaluminum compound, a titanium atom, a magnesium atom, a halogen atom and an electron donating compound is preferable.

  Examples of the organoaluminum compound include trialkylaluminum such as trimethylaluminum and triethylaluminum, dialkylaluminum halide such as dimethylaluminum chloride and diethylaluminum chloride, alkylaluminum sesquihalide such as methylaluminum sesquichloride and ethylaluminum sesquichloride, and methylaluminum. Examples thereof include alkylaluminum dihalides such as dichloride and ethylaluminum dichloride, and alkylaluminum hydrides such as diethylaluminum hydride.

  Titanium tetrachloride, tetraethoxy titanium, tetrabutoxy titanium, etc. are mentioned as a titanium compound used as the supply source of the said titanium atom.

  Examples of the magnesium compound that serves as a supply source of the magnesium atom include dialkyl magnesium, magnesium dihalide, dialkoxy magnesium, and alkoxy magnesium halide. Among these, magnesium dihalide is preferable.

  Examples of the halogen atom include fluorine, chlorine, bromine and iodine. Among them, chlorine is preferable. The halogen atom is usually supplied from the above-described titanium compound or magnesium compound, but may be supplied from another halogen source such as an aluminum halide, a silicon halide, or a tungsten halide.

  Electron-donating compounds include alcohols, phenols, ketones, aldehydes, carboxylic acids, oxygen-containing compounds such as organic or inorganic acids and their derivatives, nitrogen-containing compounds such as ammonia, amines, nitriles, and isocyanates. Compound etc. are mentioned. Among these, inorganic acid esters, organic acid esters, and organic acid halides are preferable, and silicate esters, phthalic acid esters, acetic acid cellosolve esters, and phthalic acid halides are more preferable.

  Examples of the silicate ester include t-butyl-methyl-dimethoxysilane, t-butyl-methyl-diethoxysilane, cyclohexyl-methyl-dimethoxysilane, and cyclohexyl-methyl-diethoxysilane.

  As polymerization conditions for the production of the propylene-based resin composition, for example, propylene and other monomers as necessary are supplied in the first stage, and the temperature is preferably 50 to 150 ° C. in the presence of the catalyst, preferably The main component of propylene is a residence time of 0.5 to 10 hours, preferably 1 to 5 hours, with 50 to 100 ° C. and a partial pressure of propylene of 0.5 to 4.5 MPa, preferably 1.0 to 3.5 MPa. Polymerize the monomer as a component to produce a polymer component having a melting point peak temperature of 150 ° C. or higher mainly composed of propylene, and then, in the second stage, ethylene, propylene, and other carbon atoms of 8 or less if necessary Other α-olefins and, if necessary, further other monomers are supplied, and the temperature is 50 to 150 ° C., preferably 50 to 100 ° C. in the presence of the catalyst. With a partial pressure of 0.3 to 4.5 MPa, preferably 0.5 to 3.5 MPa, with a residence time of 0.5 to 10 hours, preferably 1 to 5 hours, ethylene, propylene, α-olefin and optionally Other monomers can be copolymerized to produce a copolymer of α-olefin having 8 or less carbon atoms other than ethylene, propylene and propylene.

  The polymerization can be carried out by any of batch, continuous and semi-batch methods. The first stage polymerization is preferably carried out in the gas phase or liquid phase, and the second and subsequent polymerizations are preferably carried out in the gas phase or liquid phase, particularly in the gas phase.

  In the above polymerization, by adjusting the amount of monomer to be polymerized in each stage, the type of catalyst used, the polymerization conditions (temperature, pressure, etc.), the composition of charged monomers, the melting point peak temperature mainly composed of propylene can be obtained. The amount of a copolymer of propylene and other α-olefin having 8 or less carbon atoms, the essential component of which is a polymer component of 150 ° C. or higher, and propylene and ethylene can be adjusted, and is defined by the present invention. The propylene resin composition can be produced so that the characteristics of the propylene resin composition to be obtained can be obtained.

  The copolymer phase (island portion) of propylene and other α-olefin having 8 or less carbon atoms, containing propylene and ethylene as essential components, preferably has a sphere equivalent average diameter of 0.1 to 1 μm. Preferably it has a size of about 0.1 to 0.2 μm. If the size of the island portion of the copolymer of propylene and another α-olefin having 8 or less carbon atoms, containing propylene and ethylene as essential components, is larger than this, the effect of the present invention is hardly obtained. The sphere equivalent average diameter is an average diameter of spheres having the same volume as each island-like copolymer phase.

  By the polymerization as described above, propylene and ethylene having 8 or less carbon atoms other than propylene and ethylene as essential components in a matrix composed of a polymer component having a melting point peak temperature of 150 ° C. or more mainly composed of propylene. A propylene-based resin composition having a sea-island structure including a copolymer phase with an α-olefin and having the above characteristics can be obtained. This material has a sea-island structure in which a high molecular weight elastomer is uniformly finely dispersed in a matrix mainly composed of polypropylene, and is excellent in flexibility and elastic recovery.

  Although the said propylene-type resin composition used for this invention can be manufactured as mentioned above, it is also available as a commercial item. As a commercially available product, for example, “Zeras 7023” manufactured by Mitsubishi Chemical Corporation can be preferably used.

  The surface layer of the cutting mat of the present invention contains the above propylene-based resin composition as a main component, but may contain other polymers as long as the effects of the present invention are not impaired. Examples of polymers that can be blended in the propylene-based resin composition include conventionally known propylene homopolymers, crystalline polypropylenes such as random copolymers, block copolymers, ethylene and vinyl acetate, Ethylene copolymers such as copolymers with ethyl acrylate or ethyl methacrylate, ethylene and copolymers of α-olefins such as propylene, butene, hexene and octene, conjugated dienes such as styrene with butadiene and isoprene And diblock, triblock or random copolymer and hydrogenated product thereof.

  Furthermore, the propylene-based resin composition includes various inorganic fillers such as calcium carbonate, silica, talc, mica, coloring pigments, antioxidants, light stabilizers, and lubricants, as long as the effects of the present invention are not impaired. Various additives such as an antistatic agent, a dispersing agent, a neutralizing agent, a flame retardant, and an antiblocking agent may be blended.

  Specifically, the amount of these other polymers and additives is about 40% by weight or less for crystalline polypropylene, about 50% by weight or less for polyethylene resin, and styrene based on the whole composition. The resin is preferably about 60% by weight or less, and the inorganic filler is preferably about 20% by weight or less. The surface layer of the cutting mat of the present invention has the above-mentioned “mainly comprising a propylene-based resin composition”, for example, in the above-mentioned range, the components other than the propylene-based resin composition are impaired in the effects of the present invention. It means that it may be included in the range which is not.

  The cutting mat of the present invention may be composed of a single layer mainly composed of the propylene-based resin composition, but is a base material for imparting desired mechanical properties to the cutting mat such as mechanical strength and rigidity. It is preferable to form a laminate in which a surface layer mainly composed of the propylene-based resin composition is laminated on the layer.

  As the material of the base material layer, any material that can obtain desired mechanical properties can be used, but it is preferable to use a material other than a material that gives load to the environment such as vinyl chloride. Preferable materials include, for example, propylene homopolymer (isotactic or syndiotactic) polymerized using a Ziegler Natta or metallocene catalyst, a random type or a block type copolymer and the like that have been conventionally used. And a resin composition mainly composed of crystalline polypropylene. In particular, a propylene homopolymer is preferable from the viewpoint of mechanical strength and rigidity.

  Specific mechanical properties of the material of the base material layer include a flexural modulus (JIS K7171) of 700 MPa or more, preferably 1,000 MPa or more, and a Rockwell hardness (JIS K7202-2) of 50 or more, preferably It is preferable that it is 70 or more, and a crystalline polypropylene having such properties and a resin composition containing the same as the main component are mentioned as preferable materials.

  The polymer or resin composition used for the base material layer may be a general-purpose polyethylene (high density polyethylene, low density polyethylene, linear low density polyethylene) or ethylene and acetic acid as long as the effects of the present invention are not impaired. A copolymer with vinyl, methyl methacrylate or the like may be added. Further, inorganic fillers such as calcium carbonate, silica and talc, coloring pigments and the like may be added.

  The amount of the polymer and additive to be added is preferably 30% by weight or less for polyethylene or ethylene copolymer and 50% by weight or less for inorganic filler with respect to the base material. When the amount of polyethylene or ethylene-based copolymer exceeds 30% by weight, the rigidity of the base material layer decreases, and when the amount of the inorganic filler exceeds 50% by weight, the strength of the base material layer decreases.

  More preferably, the cutting mat of the present invention has a three-layer structure in which a surface layer mainly composed of the propylene-based resin composition is provided on both surfaces of the base material layer as described above.

  By using the three-layer structure as described above, for example, a base material layer made of crystalline polypropylene is sandwiched between two surface layers provided on both sides, so that curling of the sheet due to crystalline polypropylene is prevented. This is preferable. In addition, there are advantages that both surfaces can be used as a cutting mat surface having excellent cutting properties, and soft propylene-based resin is less slippery, which contributes to improvement in workability when using the cutting mat.

  The cutting mat of the present invention can be produced by forming a sheet of the resin composition by a T-die method, a calendar method, or the like when it is composed of a single layer mainly composed of the propylene-based resin composition. In the case of a laminate as described above, a co-extrusion using a multilayer T-die corresponding to the number of constituent layers is made by arbitrarily adding an additive polymer, a resin composition, and the material of each constituent layer blended with additives. Obtained by extruding each layer simultaneously. Alternatively, the sheet constituting the surface layer is prepared by extrusion molding or calendering, and the surface layer sheet is laminated on one side or both sides of the base layer when the base layer is formed by single layer extrusion. It is done. Furthermore, the sheets constituting each layer formed in advance may be laminated by hot press molding and hot pressed.

  The thickness of the cutting mat of the present invention is not particularly limited as long as it is a suitable thickness for use as a cutting mat. For example, when the total thickness is 0.5 to 3 mm and a laminate is used, the base material layer The thickness of the surface layer is generally 0.2 to 2.8 mm, and the thickness of the surface layer is generally in the range of 0.1 to 0.2 mm.

  Further, the surface of the surface layer may be subjected to mechanical processing such as embossing to give fine irregularities, and ruled lines, patterns of various designs, etc. may be printed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited by a following example. In the following text, parts and% are parts by weight and% by weight unless otherwise specified.

Examples 1-3 and Comparative Examples 1-3
(1) Preparation of sheet for cutting mat One sheet for base layer with 20 cm square and thickness: 1.5 mm for each of the combinations of base layer and surface layer materials of Examples and Comparative Examples shown in Table 1 And two sheets for surface layer having a thickness of 0.5 mm were formed by hot pressing at 200 ° C., and then these three sheets were laminated with the sheet for base layer sandwiched between the sheets for surface layer, and 200 ° C. × 3 A cutting mat having a total thickness of 2.4 mm was formed by hot pressing in minutes.

ZELAS 7023 (Mitsubishi Chemical) is a propylene-based soft resin composition having a sea-island structure containing a copolymer phase of ethylene and propylene having a diameter of about 0.1 to 0.2 μm in a homopropylene matrix having a melting point peak temperature of 164 ° C. In addition, the xylene-soluble content at room temperature is 35% by weight, and the content of α-olefin other than propylene in the xylene-soluble content at room temperature is 19% by weight.
Table 2 shows the trade names and physical properties of other resins used in the examples and comparative examples.

(2) Performance evaluation (2-1) Flexibility (tensile modulus) of surface layer sheet
According to JIS K7113 “Plastic Tensile Test Method”, the distance between chucks: 80 mm for the test pieces obtained by punching each of the surface layer sheets having a thickness of 0.5 mm prepared in (1) above with a JIS No. 2 dumbbell. The tensile test at room temperature was performed at a crosshead speed of 50 mm / min, and an elastic modulus serving as a measure of flexibility was obtained. The results are shown in Table 2. In the table, an elastic modulus of 300 MPa or less was shown as ◯ (good flexibility) and a case of exceeding 300 MPa as x (insufficient flexibility).

(2-2) Elastic recovery of the scar of the cutting mat (the width of the scar after 12 hours)
After running a commercially available cutter knife (blade thickness: 0.4 mm) on the cutting mat created in the above (1) while applying a load of 2 kg at a speed of 1 m / min, 12 hours later The width of the scar was measured with a stereomicroscope. The results are shown in Table 3. In the table, the case where the width of the scar is 0.2 mm or less is shown as ◯ (good recoverability), and the case where it exceeds 0.2 mm is shown as x (poor recoverability).

  Table 1 shows the composition of the resin composition constituting the base layer sheet and surface layer sheet used in the examples and comparative examples, and Table 2 shows the trade names and physical properties of the resins used in the examples and comparative examples. Table 3 shows the results of the performance evaluation.

  As is apparent from the above results, it can be seen that the cutting mat of the present invention exhibits a remarkably superior knife scar elastic recovery as compared with a cutting mat using a conventionally used material.

The cutting mat of the present invention is excellent in molding processability, flexibility, and resiliency of scars, and even when continuously used, excellent cutting properties such as paper do not deteriorate. Moreover, it can be set as the cutting mat which does not use vinyl chloride.

Claims (8)

Copolymerization of propylene and other α-olefins having 8 or less carbon atoms, containing propylene and ethylene as essential components in a matrix composed of a polymer component having a melting point peak temperature of 150 ° C. or higher mainly composed of propylene. A propylene-based resin composition having a sea-island structure including a combined phase,
(1) The xylene solubles at room temperature is 10 to 60% by weight,
(2) The content of the α-olefin having 2 to 8 carbon atoms other than propylene in the xylene-soluble component at room temperature is 5 to 20% by weight,
(3) A cutting mat having a surface layer mainly composed of the propylene-based resin composition, wherein the number average molecular weight of xylene solubles at room temperature is in the range of 50,000 to 200,000. The propylene-based resin composition is
(1) The xylene solubles at room temperature is 20 to 50% by weight,
(2) The cutting mat according to claim 1, wherein the content of the α-olefin having 2 to 8 carbon atoms other than propylene in the xylene-soluble component at room temperature is 10 to 18% by weight. .   The propylene-based resin composition is essentially composed of 10 to 60% by weight of propylene as a main component and a polymer component having a melting point peak temperature of 150 ° C. or higher and 40 to 90% by weight of propylene and ethylene with respect to the entire composition. The cutting mat according to claim 1 or 2, comprising a copolymer of propylene and another α-olefin having 8 or less carbon atoms as a component.   The copolymer phase of propylene and another α-olefin having 8 or less carbon atoms, containing propylene and ethylene as essential components, has a sphere equivalent diameter and an average size of 0.1 to 1 µm. The cutting mat in any one of -3.   A step in which the propylene-based resin composition polymerizes a monomer containing propylene as a main component, and a step in which a monomer containing ethylene, propylene, and other α-olefin having 8 or less carbon atoms as necessary is polymerized. The cutting mat according to any one of claims 1 to 4, wherein the cutting mat is produced by multistage polymerization.   The cutting mat according to any one of claims 1 to 5, wherein a surface layer made of the propylene-based resin composition is provided on a base material layer mainly composed of crystalline polypropylene.   The cutting mat according to claim 8, which has a three-layer structure in which surface layers are provided on both surfaces of a base material layer. The cutting mat according to claim 6 or 7, wherein the surface layer has a thickness of 0.1 to 0.2 mm.