WO2022208605A1

WO2022208605A1 - Adhesive tape

Info

Publication number: WO2022208605A1
Application number: PCT/JP2021/013274
Authority: WO
Inventors: 雄志浅井; 優紀岡村
Original assignee: 株式会社寺岡製作所
Priority date: 2021-03-29
Filing date: 2021-03-29
Publication date: 2022-10-06

Abstract

In order to provide an adhesive tape which hardly deforms while satisfying required characteristics expected of adhesive tape, such as adhesive force and holding power, is capable of suppressing stickiness of side surfaces, and is capable of suppressing the emission amount of greenhouse gas, used is an adhesive tape that has a base material which is a laminate formed by laminating a back layer on one surface of a base cloth, and that has an adhesive agent layer arranged on the surface of the base material that is opposite from the back layer. The back layer is configured from a thermoplastic resin including polyolefin, and the adhesive agent layer contains natural rubber, a wood-based filler, a plant-derived plasticizer, and a tackifier.

Description

Adhesive tape

The present invention relates to adhesive tapes that are suitably used for packaging, curing, and other purposes.

Conventionally, a cloth adhesive tape having a structure in which a polyethylene resin layer is provided on one side of a woven fabric using rayon spun yarn as warp and weft, and an adhesive layer is provided on the other side, has been used for packaging, curing, etc. It is used in applications (for example, Patent Document 1). The adhesive of the adhesive tape used for such applications is produced by masticating a rubber-based adhesive, such as natural rubber, to reduce the molecular weight, and kneading with each compounding material. However, in an adhesive tape using such a rubber-based adhesive, since the rubber component has a low molecular weight due to mastication, the cohesive force of the adhesive decreases, and when the adhesive tape is wound into a roll, , there are problems such as deformation of the roll and stickiness on the side surface of the roll due to the rubber-based pressure-sensitive adhesive protruding from the side surface of the roll.

Cloth adhesive tapes used for packaging, curing, etc. are packed after manufacturing, delivered to retail stores or warehouses of retail stores, displayed in stores, or delivered directly to users. Therefore, there is a risk that the packaging material will stick to the tape side surface due to deformation due to contact between the tapes during delivery, or a load will be applied to the tape side surface, causing problems such as difficulty in peeling off the packaging material. In particular, tapes with a thick adhesive layer are susceptible to this effect, and there is a demand for suppression of deformation and side stickiness.

On the other hand, adhesive tapes are peeled off and incinerated after being used for packaging and curing purposes. It becomes a problem. Patent Document 2 can be cited as a technique for suppressing greenhouse gas emissions from adhesive tapes. Patent Document 2 discloses a technique for suppressing greenhouse gas emissions from adhesive tapes, which uses a bio-based material for the base material. However, the ratio of biobased materials to the entire material is low, and there is a problem that the effect of suppressing greenhouse gas emissions is limited.

In addition, conventionally, the rubber-based adhesive used in adhesive tapes contains a large amount of heavy calcium carbonate as a filler, and has been widely used due to its low cost and availability. However, when an adhesive tape containing a large amount of heavy calcium carbonate is incinerated, carbon dioxide is generated due to decarboxylation of the heavy calcium carbonate, resulting in a large amount of greenhouse gas emissions.

Therefore, it is required to use a wood-based filler that can replace heavy calcium carbonate in the adhesive tape to suppress greenhouse gas emissions from incineration. However, when wood-based fillers are used as fillers in adhesives, the dispersibility of the filler in the adhesive deteriorates, reducing the ability to coat the base material and impairing the smoothness of the adhesive surface. There is a problem of causing a decrease in

In addition, the rubber-based adhesive softens the rubber component, which is the main ingredient, to improve the coating properties on the base material and the smoothness of the adhesive surface, thereby improving the adhesion to the adherend. added. However, when mineral oil-based plasticizers, which have been conventionally used as plasticizers, are used in pressure-sensitive adhesives with wood-based fillers as fillers, the mineral-oil-based plasticizers bond with natural rubber and wood-based fillers due to their molecular structure. is less likely to occur. Therefore, the bonding strength (cohesive strength) between the respective components of the adhesive cannot be obtained, and there is a problem that among the properties required for the adhesive tape, for example, the holding power is lowered.

Japanese translation of PCT publication No. 2011-519989 WO2015/056499

It is an object of the present invention to provide adhesive tapes that are resistant to deformation, capable of suppressing stickiness on the side surfaces, and suppressing greenhouse gas emissions while satisfying required properties such as adhesive strength and holding power required for adhesive tapes. To provide an adhesive tape capable of

The inventors of the present invention have made intensive studies to solve this problem, and as a result, have solved the problem by adopting the following configuration.

That is, the pressure-sensitive adhesive tape of the present invention comprises a substrate, which is a laminate obtained by laminating a back layer on one surface of a base fabric, and an adhesive disposed on the surface of the substrate opposite to the back layer. and a layer, wherein the back layer is composed of a thermoplastic resin containing polyolefin, and the adhesive layer includes natural rubber, a wood-based filler, a plant-derived plasticizer, and a tackifier An adhesive tape containing an agent.

The pressure-sensitive adhesive tape of the present invention uses a plant-derived woody filler as a filler of the pressure-sensitive adhesive, so that the shape stability of the pressure-sensitive adhesive increases, and the tape is less deformed than mineral-derived fillers such as heavy calcium carbonate. It is hard to stick, and the stickiness of the side of the tape is also reduced. In addition, by using a plant-derived plasticizer as a softening component of the adhesive, the smoothness of the adhesive surface can be maintained even if a woody filler is used, and deterioration of required properties can be suppressed. In addition, since it contains more plant-derived materials than before, it is possible to suppress the increase of carbon dioxide in the atmosphere due to incineration, and it is also possible to prevent carbon dioxide emissions due to decarboxylation of heavy calcium carbonate. is.

The pressure-sensitive adhesive tape of the present invention comprises a substrate, which is a laminate obtained by laminating a back layer on one surface of a base fabric, and an adhesive layer disposed on the surface of the substrate opposite to the back layer. is an adhesive tape having

<Adhesive layer>
The adhesive layer contains natural rubber, a wood-based filler, a plant-derived plasticizer, and a tackifier. Each component will be described below.

(natural rubber)
The adhesive component used in the adhesive layer of the present invention contains natural rubber.
Natural rubber is solidified sap (latex) collected from a rubber tree called Hevea brasiliens. Natural rubber consists of sheet rubber that is coagulated with acids such as formic acid, dried, and made into sheets, and cup lumps that are naturally coagulated in cups used to collect latex at rubber plantations, which are crushed, washed, and dried. It is roughly classified into block rubber manufactured by post-pressing.
The term natural rubber in this specification does not include liquid natural rubber, which will be described later, unless otherwise specified.

Sheet rubber is classified according to the "International Quality and Packaging Standards for Various Grades of Natural Rubber" (commonly known as the "Green Book"), and the varieties are determined by raw materials and manufacturing methods. There are ribbed smoked sheet (RSS), which is obtained by drying a sheet obtained from rubber tree sap (natural rubber latex) while smoking, and crepe, which is made by washing the solidified sap and drying it with hot air. Sheet rubber is classified into grades such as RSS#3, RSS#1, pale crepe, and sole crepe.

Block rubber is a natural rubber graded according to the ISO standard (ISO2000) after washing and drying the coagulated small granules of rubber and then press-molding it. There are standard grades TSR20 and TSR10, TSR-CV grade with hydroxylamine hydrochloride added as a viscosity stabilizer, and TSR-L grade with sodium pyrosulfite added as an anti-tarnishing agent.

When natural rubber is used as the pressure-sensitive adhesive component (main agent) of the present invention, any one of these grades may be used alone, or a plurality of grades may be used in combination, depending on the performance required for the pressure-sensitive adhesive. good.

Among these classifications and varieties, RSS#3 and TSR-CV grade natural rubber can be mainly used for the adhesive component used in the adhesive tape of the present invention. RSS #3 natural rubber has a large distribution volume and is advantageous in terms of availability and cost. TSR-CV grade natural rubber has a lower viscosity than RSS etc. Smoothness can be improved.

(woody filler)
The pressure-sensitive adhesive layer of the present invention contains a wood-based filler as a filler. Examples of woody fillers include powdery cellulose and lignin compounds. Among them, powdered cellulose exhibits the effect of reinforcing the pressure-sensitive adhesive due to its fibrous shape. In addition, since the tape is bulky, it is possible to reduce material costs by reducing the amount of adhesive that occupies the tape thickness.

Powdered cellulose includes acid-treated cellulose obtained by pulverizing cellulose raw materials such as pulp that has been acid-hydrolyzed with mineral acids (i.e., inorganic acids) such as hydrochloric acid, sulfuric acid, and nitric acid, and pulp that has not been acid-hydrolyzed. There is mechanically pulverized cellulose obtained by mechanically pulverizing cellulose raw materials such as Powdered cellulose can be appropriately selected and used according to required performance and the like.

The woody filler preferably has an average particle size of 1 μm or more and 50 μm or less. If the average particle size is 50 µm or less, the surface smoothness of the pressure-sensitive adhesive layer is not impaired. If the adhesive surface is not smooth, the adhesive tape may not have sufficient adhesiveness to the adherend and may not exhibit its adhesive performance sufficiently. If the average particle size is 1 μm or more, the desired bulkiness is obtained, the thickness of the adhesive layer is secured, the increase in the amount of adhesive in the tape thickness is suppressed, and the increase in material cost is suppressed. be able to. The average particle diameter used here is the median diameter indicated by D50.

The amount of woody filler added is preferably 10 to 250 parts by mass, more preferably 50 to 150 parts by mass, per 100 parts by mass of natural rubber. When the amount is 10 parts by mass or more, it is possible to suppress an increase in the rubber elasticity of the pressure-sensitive adhesive and to suppress a decrease in coatability when the pressure-sensitive adhesive is applied to a substrate. On the other hand, when the content is 250 parts by mass or less, deterioration of the rubber elasticity of the pressure-sensitive adhesive can be suppressed, and deterioration of the adhesive performance can be prevented.

(Plasticizer)
The pressure-sensitive adhesive layer of the present invention contains a plant-derived plasticizer as a softening component of the pressure-sensitive adhesive. Plant-derived plasticizers include liquid natural rubber, liquid farnesene rubber, soybean oil, sunflower oil, rapeseed oil, cottonseed oil, linseed oil, corn oil, canola oil, palm oil, or modified products thereof (e.g., epoxidized bean oil, etc.) can be used. Any one of these plant-derived plasticizers may be used alone, or a plurality of types may be used in combination.

By using a plant-derived plasticizer as a plasticizer for an adhesive that uses natural rubber as the main agent and wood filler as the filler, the cohesive force between the plasticizer and other components in the adhesive component can be improved. .

Among these, when liquid natural rubber is used as a plant-derived plasticizer, it is possible to suppress a rapid decrease in viscosity when the adhesive is blended, so that the dispersibility of each component of the adhesive is improved. . Moreover, when a vegetable oil such as soybean oil is used, both the vegetable oil and the woody filler have a polar group, so the affinity is high, and the dispersibility and cohesiveness of each component of the pressure-sensitive adhesive can be improved.

　Liquid natural rubber is obtained by depolymerizing natural rubber. Depolymerization methods include, for example, a method in which rubber molecules are cut by a mechanochemical reaction using a shearing force using a roll machine, a method in which a rubber solution is decomposed by a photochemical reaction by irradiating ultraviolet rays, and a method in which phenylhydrazine is decomposed. There are a method of chemical oxidative decomposition, a method of air oxidation in the presence of a radical generator, and the like.

The weight average molecular weight (Mw) of the liquid natural rubber is preferably 150,000 or less, more preferably 100,000 or less, still more preferably 50,000 or less. When the Mw is 100,000 or less, deterioration of the wettability of the pressure-sensitive adhesive layer can be suppressed, and deterioration of sticking properties at low temperatures can be prevented.

The amount of the plant-derived plasticizer to be added is preferably 5 to 50 parts by mass, more preferably 10 to 30 parts by mass, per 100 parts by mass of natural rubber. If the plasticizer is 5 parts by mass or more, the decrease in wettability of the pressure-sensitive adhesive layer can be suppressed, and the deterioration of sticking properties at low temperatures can be prevented. If the amount is 50 parts by mass or less, the plasticizer does not bleed, and contamination of adherends and changes in adhesive performance over time can be suppressed.

(Tackifier)
The pressure-sensitive adhesive layer of the present invention contains a tackifier. By using a plant-derived tackifier as the tackifier, the degree of bio-basedness can be further improved. Plant-derived tackifiers include terpene resins, terpene phenol resins, rosin resins, rosin ester resins, and the like. Among them, terpene resins are suitable because they are highly biobased and can reduce carbon dioxide emissions. Any one type of tackifier may be used alone, or a plurality of types may be used in combination.

The tackifier preferably has a softening point in the range of 70°C to 150°C. When the softening point is 70° C. or higher, a decrease in adhesive strength can be suppressed, and side stickiness can also be suppressed. In addition, when the softening point is 150° C. or lower, the compatibility with natural rubber is excellent, and a decrease in adhesive strength can be suppressed. More preferably, the softening point of the tackifier is 80°C or higher and 125°C or lower. Although the softening point has a variation of about ±5° C. in the product catalog, the center value is the above range, and this variation is included.

Terpene resins include unmodified terpene polymers such as α-pinene polymer, β-pinene polymer, and limonene polymer; Examples include modified terpene polymers modified by one or more selected treatments. Examples of modified terpene polymers include terpene phenolic resins and aromatic modified terpene resins. Any one type of these may be used alone, or a plurality of types may be used in combination.

Rosin resins include, for example, unmodified rosins such as gum rosin, wood rosin and tall oil rosin; modification of unmodified rosins by one or more treatments selected from hydrogenation, disproportionation, polymerization, chemical modification and the like; modified rosin; and various rosin derivatives. Examples of rosin derivatives include rosin esters obtained by esterifying unmodified rosin or modified rosin with alcohols; rosins modified with unsaturated fatty acids obtained by modifying unmodified rosin or modified rosin with unsaturated fatty acids; Fatty acid-modified unsaturated fatty acid-modified rosin esters; unmodified rosin, modified rosin, unsaturated fatty acid-modified rosins, or rosin alcohols obtained by reducing the carboxy group in unsaturated fatty acid-modified rosin esters; unmodified rosin, modified Metal salts of rosins (especially rosin esters) such as rosin and various rosin derivatives; rosins obtained by adding phenol to rosins such as unmodified rosin, modified rosin and various rosin derivatives with an acid catalyst and subjecting them to thermal polymerization. Phenolic resin; acid-modified rosins obtained by modifying unmodified rosin or modified rosin with acids such as acrylic acid, fumaric acid, or maleic acid; rosin esters modified with acids such as acrylic acid, fumaric acid, or maleic acid and acid-modified rosin esters. Any one type of these may be used alone, or a plurality of types may be used in combination.

The amount of tackifier added is preferably 30 to 150 parts by mass, more preferably 60 to 120 parts by mass, per 100 parts by mass of natural rubber. If the amount of the tackifier is 30 parts by mass or more, a decrease in adhesive strength can be suppressed.

(Other compounding materials)
The pressure-sensitive adhesive layer may contain ingredients known in the art in addition to the above ingredients. Examples thereof include vulcanizing agents, vulcanization accelerators, vulcanizing auxiliaries, anti-aging agents, conductive materials, peptizers, and colorants.

[Base material]
As the base material used for the pressure-sensitive adhesive tape of the present invention, a base material that is a laminate obtained by laminating a backing layer on one surface of a base fabric is used.

(base fabric)
Fiber materials that make up the base fabric include synthetic fibers such as polypropylene (PP), polyethylene terephthalate (PET), nylon (Ny), rayon, cotton, kapok, flax, ramie, hemp, jute, manila hemp, sisal hemp, and silk. Fibers derived from plants such as straw, coconut palm, and cupra can be mentioned. Any one or more of these fibers may be used in combination. Further, the mixed spinning of these materials is arbitrary and not particularly limited. Also, the base fabric may be in any form such as woven fabric, knitted fabric, non-woven fabric, etc., and is not particularly limited. From the viewpoint of increasing the degree of bio-basedness, the base fabric is preferably composed of plant-derived fibers, and rayon is particularly preferred.

(back layer)
The back layer is composed of a thermoplastic resin containing polyolefin. Polyolefins include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer. polymer (EEA), and the like. From the viewpoint of increasing the degree of bio-basedness, it is preferable to use bio-polyolefin. Here, biopolyolefin means polyolefin produced from plant-derived bioethanol such as sugarcane. The method for producing biopolyolefin is not particularly limited, and various known methods can be employed. Commercially available biopolyethylene, for example, can be used as the biopolyolefin. Any one type of biopolyolefin may be used alone, or a plurality of types may be used in combination.

[Bio-based]
In the pressure-sensitive adhesive tape of the present invention, each material can be selected so that the degree of bio-based content is 50% or more. The biobased content of the adhesive tape refers to the mass ratio of the biomass-derived component to the mass of the entire adhesive tape. The biobased content of the adhesive tape can be determined according to ISO 16620-4 (Determination of biobased mass content). Specifically, the mass (A) of the entire adhesive tape and the mass (B) of the biomass-derived component are calculated, and the value is calculated by the following formula.
Bio-based degree (%) = {mass (B) / mass (A)} x 100
The higher the degree of bio-based, the more it is possible to reduce substantial carbon dioxide emissions. In the present invention, it is possible to effectively increase the biobased content of the pressure-sensitive adhesive layer, which has not been possible in the past, so that the pressure-sensitive adhesive tape can easily achieve a biobased content of 90% or more. In the case of using a copolymer or a combination of multiple types of materials, etc., if biomass-derived components are partly used and petroleum-derived components are used for the rest, biomass-derived components of each component Calculate the biobased content according to the percentage.

The biomass-derived components used in the adhesive tape of the present invention refer to renewable plant-derived organic resources, excluding materials such as fossil resources that are depleted by mining. The biomass-derived component may be, for example, the above-mentioned renewable organic resource itself, or a material obtained by chemically or biologically modifying the above-mentioned organic resource or synthesizing it using the organic resource. may be

Biomass-derived components also release carbon dioxide when incinerated, but the amount of carbon dioxide released is the same as the amount of carbon dioxide that plants absorb from the atmosphere through photosynthesis during the growth process. can be considered to have no effect. Such a way of thinking is called carbon neutral, and by using a biomass-derived component as a constituent material of the adhesive tape, it is possible to reduce the amount of carbon dioxide.

[Method for producing adhesive tape]
The production method of the adhesive tape is not particularly limited, and it can be produced by a conventionally known method. For example, the base material is formed by molding the fibers constituting the base fabric into a desired woven fabric or the like to form the base fabric, and laminating an olefin resin on one side of the base fabric to form a back layer, thereby obtaining a base material that is a laminate. . As a lamination method, any method may be used, such as laminating an olefin resin film on a base fabric and thermocompression bonding, or heat-melting an olefin resin and extruding it onto the base fabric. Also, the back layer can be formed after surface treatment is applied to the surface of the woven fabric or the like forming the laminate layer. The laminate layer can also be formed on the opposite side of the backing layer of the base fabric.

Next, the pressure-sensitive adhesive composition that has been mixed and prepared separately is applied to the surface of the substrate opposite to the surface on which the back layer is formed (also referred to as the "other surface") to form an adhesive layer. The surface of the base material to which the pressure-sensitive adhesive composition is applied may be subjected to surface treatment in order to improve adhesion.

　As a surface treatment, physical or chemical anchor treatment (AC treatment) is applied. Examples of physical treatment include corona treatment, UV treatment, and sputtering treatment, and examples of chemical treatment include treatment of applying a resin selected from organotitanium, isocyanate, polyethyleneimine, polybutadiene, and the like. From the viewpoint of increasing the biobased content, physical treatment is preferred.

The pressure-sensitive adhesive layer is formed by coating with various coating devices. Examples of coating devices include a calendar coater, roll coater, die coater, lip coater, Meyer bar coater, gravure coater and the like.
In addition, if necessary, a release layer may be formed on the outer surface of the back layer to prevent the adhesive from remaining on the back side when wound into a roll.

The thickness of the substrate is preferably in the range of 50-500 μm, more preferably in the range of 100-300 μm. When the thickness is 100 µm or more, the rigidity of the base material is improved and the workability is improved. For the adhesive layer, for example, the coating amount per side can be selected from the range of 30 to 400 g/m ² according to the performance and application required for the adhesive tape, and the thickness of the tape can be selected according to the performance and usage required for the adhesive tape. It can be selected from the range of 80 to 900 μm depending on the application.

The manufactured adhesive tape is wound into a roll and cut to a specified width. The cut adhesive tape is packed by protecting the sides with, for example, a polyethylene film or by individually wrapping each roll to prevent the sides of the adhesive tape from coming into contact with each other. Since the pressure-sensitive adhesive tape according to the present invention can effectively suppress stickiness on the side surface of the tape, the side surface protective film and the packaging material can be easily peeled off. Furthermore, by suppressing side stickiness, packing without using a protective film or packaging material is also possible.

The present invention will be specifically described below with reference to examples. However, the present invention is not limited only to these examples. In addition, the manufacturer's catalog values are used for the physical property values of each raw material. Also, the presence or absence of "average" depends on the description in the catalog.

Example 1
A woven cloth was woven using 30-count rayon yarns for both the warp and weft so as to have a warp density of 45 threads/inch and a weft density of 35 threads/inch.
Biomass low-density polyethylene (manufactured by BRASKEM SA, trade name “SBC818”, density 0.918 g/cm ³ , hereinafter referred to as “Bio-LDPE”) was applied to one surface of this woven fabric at a processing temperature of 300 ° C. A substrate having a total thickness of 200 μm was produced by extrusion lamination using a T-die.
A pressure-sensitive adhesive composition was prepared by mixing the following base agent, filler, plasticizer and tackifier. This pressure-sensitive adhesive composition was applied to the other side of the woven fabric by a calender coating machine so as to have a film thickness of 100 µm to obtain a pressure-sensitive adhesive tape having a total thickness of 300 µm. The bulk density of powdered cellulose (KC Floc W-200) measured by the method described later was 0.33 g/cm ³ .

Example 2
In the same manner as in Example 1, except that liquid natural rubber having a weight average molecular weight (Mw) of 80,000 (manufactured by DPR INDUSTRIES INC, trade name “DPR-400”) was used as the plasticizer. Got the sticky tape.

Example 3
A pressure-sensitive adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Example 1 except that 170 parts by mass of lignin powder (Nippon Paper Industries, Sanex SCP) was used as the filler. The bulk density of the lignin powder (Sanex SCP) measured by the method described later was 0.48 g/cm ³ .

Example 4
An adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Example 1 except that white strained soybean oil (manufactured by J-NIKKA Partners, trade name “Nikka white strained soybean oil”) was used as the plasticizer.

Example 5
An adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Example 1, except that epoxidized soybean oil (manufactured by ADEKA, trade name “ADEKA CIZER O-103P”) was used as the plasticizer.

Example 6
An adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Example 1 except that rapeseed white oil (manufactured by J-NIKKA Partners, trade name “Nikka rapeseed white oil”) was used as the plasticizer.

Example 7
An adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Example 1 except that linseed oil (manufactured by Nisshin OilliO Co., Ltd., trade name “Nissin linseed oil”) was used as the plasticizer.

Example 8
A pressure-sensitive adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Example 1, except that natural rubber (CV60) was used as the main agent.

Example 9
An adhesive tape having a total thickness of 300 μm was prepared in the same manner as in Example 1 except that 120 parts by mass of powdered cellulose (manufactured by Nippon Paper Industries Co., Ltd., trade name “KC Flock W-400”) having an average particle size of 24 μm was used as the filler. Obtained. The bulk density of powdered cellulose (KC Floc W-400) measured by the method described later was 0.46 g/cm ³ .

Example 10
An adhesive tape having a total thickness of 300 μm was prepared in the same manner as in Example 1 except that the filler was 80 parts by mass of cellulose powder having an average particle size of 37 μm (manufactured by Nippon Paper Industries, trade name “KC Flock W-100”). Obtained. The bulk density of powdered cellulose (KC Floc W-100) measured by the method described later was 0.29 g/cm ³ .

Example 11
An adhesive tape with a total thickness of 300 μm was prepared in the same manner as in Example 1 except that the filler was 40 parts by mass of powdered cellulose (manufactured by Nippon Paper Industries Co., Ltd., trade name “KC Flock W-50”) having an average particle size of 45 μm. Obtained. The bulk density of powdered cellulose (KC Flock W-400) measured by the method described later was 0.14 g/cm ³ .

Example 12
In the same manner as in Example 9, except that a liquid natural rubber having a weight average molecular weight (Mw) of 80,000 (manufactured by DPR INDUSTRIES, product name "DPR-400") was used as the plasticizer. Got the sticky tape.

Example 13
A pressure-sensitive adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Example 1 except that a terpene resin (trade name “YS Resin PX1250” manufactured by Yasuhara Chemical Co., Ltd., softening point 125±5° C.) was used as the tackifying resin.

Example 14
An adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Example 1 except that a terpene resin (manufactured by Yasuhara Chemical Co., Ltd., trade name “S Resin PX800”, softening point 80±5° C.) was used as the tackifying resin.

Comparative example 1
Low-density polyethylene (manufactured by ENEOS NUC Co., Ltd., trade name “NUC8008”, density 0.918 g/cm ³ , hereinafter referred to as “LDPE”) was applied to one surface of the same woven fabric as in Example 1 at a processing temperature of 300. Example except that a film was formed by extrusion lamination using a T-die at ° C. and a total thickness of 200 μm was used as the base material, and mineral oil (manufactured by EMG Lubricants LLC, trade name “Mobiltherm 610”) was used as the plasticizer. An adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Example 1.

Comparative example 2
An adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Comparative Example 1 except that 170 parts by mass of lignin powder (Nippon Paper Industries, Sanex SCP) was used as the filler.

Comparative example 3
Example 1 except that a mineral oil (manufactured by EMG Lubricants LLC, trade name "Mobiltherm 610") was used as the plasticizer, and 200 parts by mass of ground calcium carbonate (manufactured by Maruo Calcium Co., Ltd.) having a particle size of 12 μm was used as the filler. A pressure-sensitive adhesive tape having a total thickness of 300 μm was obtained in the same manner as above. The bulk density of heavy calcium carbonate measured by the method described later was 0.99 g/cm ³ .

Comparative example 4
An adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Comparative Example 3 except that 200 parts by mass of starch powder having a particle size of 10 μm (Hayashi Pure Chemical Co., Ltd., primary starch (soluble)) was used as the filler. The bulk density of the starch powder measured by the method described later was 0.65 g/cm ³ .

Comparative example 5
A pressure-sensitive adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Example 1 except that 200 parts by mass of heavy calcium carbonate (manufactured by Maruo Calcium) having a particle size of 12 μm was used as the filler.

Comparative example 6
An adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Comparative Example 1 except that 200 parts by mass of heavy calcium carbonate (manufactured by Maruo Calcium Co., Ltd.) having a particle size of 12 μm was used as the filler.

Reference example 1
An adhesive tape having a total thickness of 300 μm was prepared in the same manner as in Example 1 except that 100 parts by mass of a terpene resin (manufactured by Yasuhara Chemical Co., Ltd., trade name “YS Resin PX300”, softening point 70 ± 5 ° C.) was used as a tackifier. Obtained.

Reference example 2
A pressure-sensitive adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Example 1, except that the amount of the filler was changed to 5 parts by mass.

Reference example 3
A pressure-sensitive adhesive tape having a total thickness of 300 μm was obtained in the same manner as in Example 1, except that the amount of the filler was changed to 300 parts by mass.

<Evaluation method>
Various properties of tape samples obtained as Examples, Comparative Examples and Reference Examples were evaluated by the following methods. The results are shown in Tables 2-4.

[Adhesive force]
The adhesive force was measured according to 10 (adhesive force) of JIS Z 0237 (testing methods for adhesive tapes and adhesive sheets). However, the test conditions were as follows. [Adhesive tape width: 10 mm, peeling angle: 180 degrees, test temperature: 23 degrees Celsius]

[Holding power]
The holding power was measured according to 13 (holding power) of JIS Z 0237 (testing methods for adhesive tapes and adhesive sheets). However, the test conditions were as follows. [Adhesive tape area: width 25 mm x length 25 m, weight: 1000 g, test temperature: 40°C]

[Constant load peeling]
A tape having a width of 10 mm was adhered to a stainless steel (SUS304BA) plate under an environment of 23° C. and 50% RH, and crimped by reciprocating a 2 kg rubber roller once. After being left in the same environment for 30 minutes, a weight of 100 g was hung from the edge of the tape, and a load was applied in the direction of 90 degrees, and the time until the tape dropped at room temperature (23°C) was measured.

[Yield point load]
A roll-shaped sample with a width of 50 mm and a length of 25 m is sandwiched between two parallel plates in which only the sides of the tape are in contact in an environment of 23 ° C and 50% RH, and a load is applied with a compression tester until it breaks. The stress was measured to obtain the yield point load value.

[Side stickiness]
A roll-shaped sample having a width of 50 mm and a length of 25 m was used, and polyethylene packing was placed on the side surface of the roll. 5 rolls of this were left in a dryer adjusted to 40° C. for 28 days, and after returning to room temperature, the stickiness on the side surface of the bottom roll was evaluated according to the following criteria.
◯: The polyethylene packing can be easily peeled off.
Δ: Although the polyethylene packing can be peeled off, resistance is felt when it is peeled off.
x: The polyethylene packing cannot be easily peeled off.

[Bulk density]
After the filler was filled up to the opening of a 200 ml graduated cylinder without applying a load, the graduated cylinder was allowed to fall freely on a desk from a height of 10 mm, and the legs of the graduated cylinder collided with the top plate of the desk. After repeating this collision 10 times, the volume of the filler was obtained from the memory of the graduated cylinder. Next, the filler was taken out from the graduated cylinder, the mass was measured, and the bulk density of the filler was obtained from the following formula (n=10 times arithmetic mean).
Bulk density (g/cm3) = mass of filler (g)/volume of filler (cm3)
Further, in the present invention, the ratio of the number of parts by mass of the woody filler to 100 parts by mass of natural rubber and the bulk density of the woody filler is a numerical value represented by the following formula.
Ratio = (parts by mass of woody filler relative to 100 parts by mass of natural rubber)/(bulk density of woody filler)

As shown in Tables 2 to 4, the conventional adhesive tape (Comparative Example 3) using heavy calcium carbonate as a filler and mineral oil as a plasticizer has a low degree of bio-based content and a large amount of side stickiness. It was something. In addition, in Comparative Examples 1 and 2 using cellulose or lignin as a filler, side stickiness was reduced, but compared with each example, there was resistance when peeling off the polyethylene packing, and side stickiness was not improved. was not satisfactory. In Comparative Example 5, in which plant-derived liquid natural rubber was used as the plasticizer and heavy calcium carbonate was used as the filler, side stickiness was not improved. Furthermore, even with the same polysaccharide composed of glucose, when starch powder was used as a filler (Comparative Example 5), side stickiness was much like in Comparative Example 3, and there was no improvement effect.

On the other hand, in the present invention, by using a wood-based filler and a plant-derived plasticizer, it is possible to realize a pressure-sensitive adhesive tape that has a high bio-based degree, satisfies various properties required for pressure-sensitive adhesive tape, and suppresses side stickiness. was made.

As described above, the pressure-sensitive adhesive tape in the present invention is difficult to deform from the result of the yield point load value, it is possible to suppress the stickiness of the side surface of the tape, and it can be used in various fields such as packaging and curing as well as conventional products. can be widely used for Moreover, since it is easy to make the bio-based content 90% or more, it is possible to achieve a high level of suppression of greenhouse effect (carbonic acid) gas emissions.

Claims

a base material, which is a laminate obtained by laminating a back layer on one surface of a base fabric;
and a pressure-sensitive adhesive layer disposed on the opposite side of the backing layer of the base material,
The back layer is made of a thermoplastic resin containing polyolefin,
The pressure-sensitive adhesive layer is
natural rubber and
Woody filler,
a plant-derived plasticizer;
a tackifier;
An adhesive tape containing
The adhesive layer contains 10 to 250 parts by mass of the wood-based filler, 5 to 50 parts by mass of the plant-derived plasticizer, and 30 to 150 parts by mass of the tackifier based on 100 parts by mass of the natural rubber. The adhesive tape according to claim 1, wherein
The adhesive tape according to claim 1 or 2, wherein the adhesive has a ratio of the number of parts by mass of the wood-based filler to the bulk density of the wood-based filler with respect to 100 parts by mass of natural rubber of 200 or more and 400 or less.
The adhesive tape according to claims 1 to 3, wherein the wood-based filler is powdered cellulose.
The adhesive tape according to any one of claims 1 to 4, wherein the plant-derived plasticizer is liquid natural rubber.
The adhesive tape according to any one of claims 1 to 5, wherein the tackifier is a plant-derived tackifier.
The adhesive tape according to claim 6, wherein the plant-derived tackifier is a terpene resin.
The adhesive tape according to any one of claims 1 to 7, wherein the tackifier contains a tackifier having a softening point of 70°C or higher and 150°C or lower.
The adhesive tape according to any one of claims 1 to 8, wherein the base fabric is composed of plant-derived fibers.
The adhesive tape according to any one of claims 1 to 9, wherein the back layer contains biopolyolefin as the polyolefin.
The adhesive tape according to claim 10, wherein the biopolyolefin is biopolyethylene.