JP7215738B2 - hot melt adhesive - Google Patents

Description

The present invention relates to hot melt adhesives.

Examples of substrates used for adhesive tapes include synthetic resin films, Japanese paper and non-woven fabrics. In addition, the adhesive tape is generally produced by coating an adhesive on the release-treated surface of a release paper or film that has been subjected to a release treatment on one side to form an adhesive layer, and then applying this adhesive layer. is transferred to the substrate surface.

In Patent Document 1, 100 parts by weight of ABA (where A is a styrene polymer block and B is a copolymer block of ethylene and butylene) and 0 to 80 parts by weight of a tackifying resin are used. An adhesive film for surface protection has been proposed, which is obtained by forming an adhesive layer comprising a composition containing the compound on a polyolefin resin film.

Further, in Patent Document 2, a laminate in which Japanese paper is superimposed on release paper is supplied to an adhesive coating device consisting of a coating roll and a base roll, and the release paper is in contact with the base roll and the Japanese paper surface is passed through the laminate. After applying the adhesive to , peel off the release paper from the Japanese paper, pass the release paper through the release roll surface that is provided between the peeled release paper and the Japanese paper, and is arranged so that only the release paper is in contact, and then A method for producing an adhesive tape by laminating Japanese paper and release paper again and drying the adhesive, wherein the surface of the peeling roll has a 50% compressive strength of 1.0 to 3.0 kg / cm ² and a thickness A method for manufacturing a double-sided pressure-sensitive adhesive tape comprising a cushioning material having a thickness of 2.5 to 4.0 mm has been proposed.

Japanese Patent Publication No. 07-116410

When the adhesive proposed in Patent Document 1 is used for a base material formed of a nonwoven fabric, the penetration of the adhesive into the nonwoven fabric is insufficient. However, there is a problem that the adhesive layer is peeled off from the base material and remains on the base material when the adhesive layer is peeled off after being attached to the substrate.

In recent years, attempts have been made to improve the speed of production lines in order to improve the production efficiency of adhesive tapes, and there has been a shift from solvent-based and water-based adhesives, which require a drying process, to hot-melt adhesives. there is

Furthermore, when laminating and integrating adhesives onto substrates, the method using a hot-melt coating machine is simpler and cheaper than the melt-extrusion method, so the switch to hot-melt adhesives is progressing. I'm in.

In order to prevent the substrate from being damaged by heat, a hot-melt adhesive is applied to the release paper or film to form a hot-melt adhesive layer, and then the hot-melt adhesive layer is applied to the substrate. It is also transferred to the material.

In this case, if the base material is a nonwoven fabric, the hot melt adhesive tends to fail to penetrate sufficiently into the nonwoven fabric.

The present invention sufficiently permeates a tape base material formed from a nonwoven fabric by a hot-melt coating machine, does not easily peel off from the nonwoven fabric after cooling, and has excellent adhesion that can be peeled off from the adherend. To provide a hot-melt adhesive having properties and excellent coatability.

The hot-melt adhesive of the present invention has the highest temperature and dynamic The difference from the highest temperature at which tan δ (loss elastic modulus G″/storage elastic modulus G′) is 1 measured by a temperature drop method at a frequency of 1 Hz by dynamic viscoelasticity measurement is 6 ° C. or more, and the dynamic viscosity The peak value of tan δ measured by the temperature rising method at a frequency of 1 Hz by elastic measurement is 1.5 or more.

Dynamic viscoelasticity measurements are taken in rotational shear mode with a fixed frequency of 1 Hz. Specifically, the dynamic viscoelasticity measurement is performed in the following manner. Prepare two sheets of release paper that has been subjected to mold release treatment. After applying a hot-melt adhesive to the release-treated surface of one release liner, the other release liner is placed on top of the hot-melt adhesive so that the release-treated surface faces the hot-melt adhesive. superimpose. At this time, the thickness of the hot-melt adhesive between the release papers is adjusted to about 1 mm, and air bubbles are prevented from entering the hot-melt adhesive. After leaving the hot-melt adhesive sandwiched between release papers at 23° C. for 24 hours, the release papers are removed to prepare a sample. This sample was subjected to dynamic viscoelasticity measurement (heating method) by heating from −40 to 100° C. at 5° C./min in rotational shear mode at a frequency of 1 Hz using a dynamic viscoelasticity measuring device. Subsequently, the temperature is lowered from 100° C. to −40° C. at a rate of 5° C./min to measure dynamic viscoelasticity (temperature drop method). As an example in FIG. 1, a tan δ (loss elastic modulus G″/storage elastic modulus G′) curve G1 measured by a temperature rising method at a frequency of 1 Hz by dynamic viscoelasticity measurement and a curve G1 at a frequency of 1 Hz by dynamic viscoelasticity measurement and a tan δ (loss elastic modulus G″/storage elastic modulus G′) curve G2 measured by a cooling method. The dynamic viscoelasticity measuring device includes, for example, a rotational rheometer (trade name “AR-G2”) available from TA Instruments.

The hot melt adhesive has the highest temperature T ₁ at which tan δ (loss elastic modulus G″/storage elastic modulus G′) measured by the temperature rising method at a frequency of 1 Hz is 1 by dynamic viscoelasticity measurement, _The difference from the highest temperature T2 at which tan δ (loss elastic modulus G″/storage elastic modulus G′) is 1 measured by a temperature drop method at a frequency of 1 Hz by viscoelasticity measurement is 6 ° C. or more, and 15 ° C. or more. is preferred, and 20°C or higher is more preferred. The hot melt adhesive has the highest temperature T ₁ at which tan δ (loss elastic modulus G″/storage elastic modulus G′) measured by the temperature rising method at a frequency of 1 Hz is 1 by dynamic viscoelasticity measurement, _The difference from the highest temperature T2 at which tan δ (loss elastic modulus G″/storage elastic modulus G′) is 1 measured by a temperature drop method at a frequency of 1 Hz by viscoelasticity measurement is preferably 80° C. or less, and 60° C. or less. is preferred, and 45°C or lower is more preferred.

Dynamic viscoelasticity measurement is a method for analyzing the mechanical properties of polymers that have both elasticity and viscosity. In the dynamic viscoelasticity measurement, the storage elastic modulus G' and the loss elastic modulus G'' can be measured, the storage elastic modulus G' is a characteristic value corresponding to elasticity, and the loss elastic modulus G'' is a characteristic value corresponding to viscosity. be.

The temperature at which tan δ (loss elastic modulus G″/storage elastic modulus G′) measured by a temperature elevation method at a frequency of 1 Hz by dynamic viscoelasticity measurement is 1 is called a crossover point, and is referred to as a crossover point, from a solid to a liquid, or , is a measure of the temperature at which it changes from liquid to solid.

The hot melt adhesive of the present invention focuses on the highest temperature T among the temperatures at which tan δ (loss elastic modulus G″/storage elastic modulus G′) measured at a frequency of 1 Hz by dynamic viscoelasticity measurement is 1, If the difference (T ₁ −T ₂ ) between the temperature T ₁ measured by the temperature rising method and the temperature T ₂ measured by the temperature decreasing method is 6° C. or more, the tape At the time of coating on the nonwoven fabric constituting the base material, the hot melt adhesive is made difficult to solidify, so that the penetration between the fibers of the nonwoven fabric constituting the tape base material is sufficient, It can improve the adhesion of the hot-melt adhesive to the tape substrate, suppress the peeling of the hot-melt adhesive from the tape substrate after cooling, and suppress the softening of the hot-melt adhesive during use. In addition, the hot-melt adhesive sufficiently permeates between the fibers of the non-woven fabric forming the tape substrate and reinforces the fiber layer. When the pressure-sensitive adhesive tape is peeled off from the adherend after use, the fiber layer of the nonwoven fabric constituting the tape substrate is not damaged, and as described above, the hot-melt adhesive adheres to the tape substrate. Since it is sufficiently permeated into the constituent nonwoven fabric, it prevents the hot-melt adhesive from remaining on the adherend when the adhesive tape is peeled off from the adherend. be able to.

Furthermore, the hot melt adhesive of the present invention has a tan δ peak value of 1.5 or more as measured by the temperature rising method at a frequency of 1 Hz by dynamic viscoelasticity measurement, so it has high viscous properties and adheres well. Easy to form intermolecular bonds with moderate strength to the body, stress acting on the interface is not concentrated in parts and requires a large amount of energy to peel off, excellent adhesion to adherends express. Therefore, the hot-melt adhesive of the present invention has excellent adhesion to the adherend, and leaves an adhesive residue on the adherend even when it is peeled off from the adherend. The pressure-sensitive adhesive tape can be peeled off from the adherend without causing the adhesive tape to peel off. In the hot-melt adhesive of the present invention, the peak value of tan δ measured by the temperature rising method at a frequency of 1 Hz by dynamic viscoelasticity measurement is preferably 10 or less, more preferably 7 or less, and particularly preferably 5 or less.

According to the hot-melt adhesive of the present invention, as described above, when the nonwoven fabric constituting the tape base material is coated, the adhesive is sufficiently spread between the fibers of the nonwoven fabric and other base materials (for example, films). It permeates and hardly separates from the base material after cooling, and can be peeled off from the adherend during use.

When applied to the nonwoven fabric constituting the tape substrate, it sufficiently permeates between the fibers of the nonwoven fabric, is less likely to be peeled off from the nonwoven fabric after cooling, and can be peeled off from the adherend during use. Hot-melt adhesives that have excellent adhesiveness and are also excellent in coating suitability are not particularly limited, but examples include styrene-ethylene-butylene-olefin crystal block copolymers and/or olefin crystal- A hot melt adhesive containing 100 parts by mass of a thermoplastic polymer containing 25% by mass or more of an ethylene/butylene-olefin crystal block copolymer, 100 to 600 parts by mass of a tackifier, and 10 to 400 parts by mass of a plasticizer ( 1) A hot melt adhesive containing 100 parts by mass of a thermoplastic polymer containing 25% by mass or more of an olefin crystal copolymer, 100 to 600 parts by mass of a tackifier, and 10 to 400 parts by mass of a plasticizer (2) is preferred. According to another aspect, 100 parts by mass of a thermoplastic polymer containing 25% by mass or more of a styrene-ethylene-butylene-olefin crystal block copolymer and/or an olefin crystal-ethylene/butylene-olefin crystal block copolymer; A hot melt adhesive (1) containing 100 to 500 parts by mass of a tackifier and 10 to 300 parts by mass of a plasticizer, and 100 parts by mass of a thermoplastic polymer containing 25% by mass or more of an olefin crystal copolymer, A hot melt adhesive (2) containing 100 to 500 parts by weight of a tackifier and 10 to 300 parts by weight of a plasticizer is more preferred.

The hot melt adhesive (1) will be described. Hot melt adhesive (1) contains a thermoplastic polymer. Thermoplastic polymers include styrene-ethylene-butylene-olefin crystal block copolymer (A) and/or olefin crystal-ethylene/butylene-olefin crystal block copolymer (B). The styrene-ethylene-butylene-olefin crystalline block copolymer is also called "styrene-(ethylene/butylene)-crystalline block copolymer". Olefin crystal-ethylene/butylene-olefin crystal block copolymer is also called "Crystalline block-(ethylene/butylene)-crystalline block copolymer". be.

The styrene-ethylene-butylene-olefin crystal block copolymer (A) and/or the olefin crystal-ethylene/butylene-olefin crystal block copolymer (B) have crystalline block segments in the molecule. In the styrene-ethylene-butylene-olefin crystal block copolymer (A) and the olefin crystal-ethylene/butylene-olefin crystal block copolymer (B), the presence or absence of crystalline block segments can be determined by a differential scanning calorimeter (DSC ) can be analyzed by After the block copolymer was heated and melted, it was cooled to −140° C. at a temperature decrease rate of 10° C./min, and then heated to 150° C. at a temperature increase rate of 20° C./min. An endothermic peak is observed at 40 to 150° C. when a crystalline block segment is included.

The styrene-ethylene-butylene-olefin crystal block copolymer (A) includes a polymer block (A1) having a styrene content of 90% by mass or more and a polybutadiene polymer having a 1,2-vinyl bond content of 30 to 70%. A block copolymer consisting of a coalescing block (A2) and a polybutadiene polymer block (A3) having a 1,2-vinyl bond content of less than 30% is obtained by adding at least 80% or more of the olefin A hydrogenated block copolymer obtained by hydrogenating saturated bonds and having a number average molecular weight of 40,000 to 700,000 is preferred. The polybutadiene polymer block (A3) becomes a crystalline block segment exhibiting a structure similar to that of low-density polyethylene upon hydrogenation. In the present invention, the number average molecular weight of the polymer is a value calculated from the GPC pattern and calibration curve of a sample of unknown molecular weight by creating a calibration curve for molecular weight and elution volume from GPC measurement of standard polystyrene with a known molecular weight. The presence or absence of crystalline block segments in the hydrogenated block copolymer can be analyzed by a differential scanning calorimeter (DSC). After the styrene-ethylene-butylene-olefin crystal block copolymer (A) is heated and melted, it is cooled to -140°C at a temperature decrease rate of 10°C/min and then to 150°C at a temperature increase rate of 20°C/min. When the temperature is raised, an endothermic peak is observed at 40 to 150° C. when the polymer contains a crystalline block segment.

In the present invention, the 1,2-vinyl bond content refers to the value calculated based on the following formula in the polymer block.
1,2-vinyl bond content (%)
= 100 × (1,2-vinyl bond amount)
/ [(1,2-vinyl bond amount) + (1,4-vinyl bond amount)]

When the content of the styrene component in the polymer block (A1) of the styrene-ethylene-butylene-olefin crystal block copolymer (A) before hydrogenation is 90% by mass or more, the adhesiveness of the hot melt adhesive is improved. improves.

The content of the polymer block (A1) in the styrene-ethylene-butylene-olefin crystal block copolymer (A) before hydrogenation is preferably 5-50% by mass, more preferably 10-40% by mass.

In the styrene-ethylene-butylene-olefin crystal block copolymer (A) before hydrogenation, the content of 1,2-vinyl bonds in the polybutadiene polymer block (A2) is preferably 30 to 70%. When the content of the 1,2-vinyl bonds is 30% or more, hydrogenation suppresses the formation of polyethylene chains, improves rubber elasticity, and improves the adhesiveness of the hot-melt adhesive. In addition, when the content of the 1,2-vinyl bond is 70% or less, the increase in the glass transition temperature due to hydrogenation is suppressed, the rubber elasticity is improved, and the adhesiveness of the hot melt adhesive is improved. can be made

The content of the polymer block (A2) in the styrene-ethylene-butylene-olefin crystal block copolymer (A) before hydrogenation is preferably 30 to 80% by mass, more preferably 35 to 70% by mass.

In the styrene-ethylene-butylene-olefin crystal block copolymer (A) before hydrogenation, the content of 1,2-vinyl bonds in the polybutadiene polymer block (A3) is preferably less than 30%. When the 1,2-vinyl bond content is less than 30%, crystalline block segments exhibiting a structure similar to that of low-density polyethylene are formed by hydrogenation, improving the cohesive strength of the hot-melt adhesive.

The content of the polymer block (A3) in the styrene-ethylene-butylene-olefin crystal block copolymer (A) before hydrogenation is preferably 5-30% by mass, more preferably 15-25% by mass.

As a method for producing the styrene-ethylene-butylene-olefin crystal block copolymer (A), first, 1,3-butadiene is polymerized using an organic lithium initiator, and then the 1,2-vinyl bond content is 30 to 30. 1,3-Butadiene is polymerized to 70% to produce blocky polybutadiene with varying 1,2-vinyl bond content. Next, a block copolymer before hydrogenation is produced by adding a vinyl aromatic compound containing 90% by mass or more of styrene to polybutadiene and polymerizing the mixture. Then, the styrene-ethylene-butylene-olefin crystal block copolymer (A) can be produced by hydrogenating the block copolymer before hydrogenation in a known manner. The styrene-ethylene-butylene-olefin crystal block copolymer (A) may contain isoprene as a monomer component. The isoprene component produces ethylene/propylene blocks after hydrogenation.

Examples of vinyl aromatic compounds include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N,N-diethyl-p-aminoethylstyrene, and vinyl and pyridine. Of these, styrene and α-methylstyrene are preferred.

Examples of organolithium compounds include n-butyllithium, sec-butyllithium, tert-butyllithium, propyllithium, amyllithium, and butyllithium/barium nonylphenoxide/trialkylaluminum/dialkylaminoethanol.

The content of the styrene component in the styrene-ethylene-butylene-olefin crystal block copolymer (A) is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and particularly preferably 15 to 35% by mass. . When the content of the styrene component is 50% by mass or less, the adhesiveness of the hot-melt adhesive is improved.

The melt flow rate of the styrene-ethylene-butylene-olefin crystal block copolymer (A) is preferably 1 to 50 g/10 minutes, more preferably 2 to 20 g/10 minutes, and more preferably 2 to 10 g/10 minutes. 3 to 8 g/10 minutes is more preferable, and 4 to 7 g/10 minutes is particularly preferable. The melt flow rate of the styrene-ethylene-butylene-olefin crystal block copolymer (A) is a value measured under conditions of 230°C and a load of 21.2N in accordance with JIS K7210 (1999). .

As the olefin crystal-ethylene/butylene-olefin crystal block copolymer (B), a polybutadiene polymer block (C) having a 1,2-vinyl bond content of 20% or less and a polybutadiene block having a butadiene portion a polymer block (D) having a 1,2-vinyl bond content of 25 to 95% and a block structure of C—(D—C)n or (C—D)m (where n is 1 or more); An integer and m is an integer of 2 or more.) is preferably a block copolymer obtained by hydrogenating 90% or more of the butadiene portion of a linear or branched block copolymer.

The polybutadiene polymer block (C) in the block copolymer before hydrogenation becomes a crystalline block segment that exhibits a structure similar to that of ordinary low-density polyethylene upon hydrogenation. The presence or absence of crystalline block segments in the block copolymer can be analyzed by a differential scanning calorimeter (DSC). After the olefin crystal-ethylene/butylene-olefin crystal block copolymer (B) was heated and melted, it was cooled to −140° C. at a temperature decrease rate of 10° C./min, and then heated to 150° C. at a temperature increase rate of 20° C./min. When the temperature is raised to 40° C. to 150° C., an endothermic peak is observed at 40 to 150° C. if the polymer contains a crystalline block segment.

The content of 1,2-vinyl bonds in the polybutadiene polymer block (C) in the block copolymer before hydrogenation is preferably 20% or less. If the 1,2-vinyl bond content is high, crystalline block segments having a structure similar to low-density polyethylene will not be formed even when hydrogenated, and the cohesive strength of the hot-melt adhesive may decrease. .

The polymer block (D) in the block copolymer before hydrogenation becomes a polymer block showing a structure similar to that of a rubber-like ethylene-butylene copolymer upon hydrogenation.

The content of 1,2-vinyl bonds in the butadiene moiety in the polymer block (D) of the block copolymer before hydrogenation is preferably 25 to 95%, more preferably 25 to 75%, and 25 to 55%. is particularly preferred. When the content of the 1,2-vinyl bond is within the above range, after hydrogenation, the crystal structure derived from the polyethylene chain or the polybutene-1 chain is suppressed, the rubber elasticity is improved, and the adhesion of the hot melt adhesive. can improve sexuality.

The content of the polybutadiene polymer block (C) in the block copolymer before hydrogenation is preferably 5 to 90% by mass, more preferably 10 to 85% by mass. When the content of the polybutadiene polymer block (C) is 5% by mass or more, the crystalline polymer block is sufficient and the cohesive strength of the hot melt adhesive can be improved. Moreover, when the content of the polybutadiene polymer block (C) is 90% by mass or less, the adhesiveness of the hot-melt adhesive is improved.

The content of the polymer block (D) in the block copolymer before hydrogenation is preferably 10 to 95% by mass, more preferably 15 to 90% by mass. When the content of the polymer block (D) is 10% by mass or more, the adhesiveness of the hot-melt adhesive is improved. Moreover, when the content of the polymer block (D) is 95% by mass or less, the crystalline polymer block is sufficient, and the cohesive force of the hot-melt adhesive can be improved.

As a method for producing the olefin crystal-ethylene/butylene-olefin crystal block copolymer (B), 1,3-butadiene is mixed with an organic lithium initiator so that the 1,2-vinyl bond content is 20% or less. After polymerization, 1,3-butadiene is polymerized so that the butadiene portion has a 1,2-vinyl bond content of 25 to 95% to produce a block copolymer before hydrogenation. An olefin crystal-ethylene/butylene-olefin crystal block copolymer (B) can be produced by hydrogenating the butadiene portion of this block copolymer to 90% or more in a known manner.

The melt flow rate of the olefin crystal-ethylene/butylene-olefin crystal block copolymer (B) is preferably 0.5 to 50 g/10 minutes, more preferably 0.5 to 10 g/10 minutes, and 1 to 5 g/10 minutes. minutes are particularly preferred. A melt flow rate of 0.5 g/10 minutes or more improves the coatability of the hot-melt adhesive. A melt flow rate of 10 g/10 minutes or less improves the coatability of the hot-melt adhesive. The melt flow rate of the olefin crystal-ethylene/butylene-olefin crystal block copolymer (B) is a value measured under conditions of 230°C and a load of 21.2N in accordance with JIS K7210 (1999). say.

The total amount of the styrene-ethylene-butylene-olefin crystal block copolymer and the olefin crystal-ethylene/butylene-olefin crystal block copolymer in the thermoplastic polymer is preferably at least 25% by mass, more preferably at least 30% by mass. 40% by mass or more is particularly preferred. The total amount of the styrene-ethylene-butylene-olefin crystal block copolymer and the olefin crystal-ethylene/butylene-olefin crystal block copolymer in the thermoplastic polymer is preferably 85% by mass or less, more preferably 80% by mass or less, 75% by mass or less is particularly preferred. When the total amount of the styrene-ethylene-butylene-olefin crystal block copolymer and the olefin crystal-ethylene/butylene-olefin crystal block copolymer is 25% by mass or more, permeation of the hot-melt adhesive to the tape base material, and the adhesion of the hot-melt adhesive to the tape base material can be improved, and peeling of the hot-melt adhesive from the tape base material after cooling can be suppressed. When the total amount of the styrene-ethylene-butylene-olefin crystal block copolymer and the olefin crystal-ethylene/butylene-olefin crystal block copolymer is 85% by mass or less, the adhesiveness of the hot melt adhesive is improved.

When the thermoplastic polymer contains either a styrene-ethylene-butylene-olefin crystal block copolymer or an olefin crystal-ethylene/butylene-olefin crystal block copolymer, the block in the thermoplastic polymer The content of the copolymer is preferably 25% by mass or more, more preferably 30% by mass or more, and particularly preferably 50% by mass or more. The content of the block copolymer in the thermoplastic polymer is preferably 85% by mass or less, more preferably 80% by mass or less, and particularly preferably 75% by mass or less. Since the reason is the same as the above, it is omitted.

Examples of the styrene-ethylene-butylene-olefin crystal block copolymer (A) include "DYNARON4600P" (trade name) manufactured by JSR Corporation. Examples of the olefin crystal-ethylene/butylene-olefin crystal block copolymer (B) include the product name "DYNARON6200P" manufactured by JSR Corporation.

The hot melt adhesive may contain a hydrogenated thermoplastic block copolymer as the thermoplastic polymer. If it contains a hydrogenated thermoplastic block copolymer, it has excellent adhesiveness.

A hydrogenated thermoplastic block copolymer is a block copolymer obtained by block copolymerizing a vinyl aromatic hydrocarbon and a conjugated diene compound, and all or part of the blocks based on the conjugated diene compound in the obtained block copolymer are hydrogen. Refers to an added block copolymer that does not have a crystalline block segment.

After heating and melting the hydrogenated thermoplastic block copolymer, it was cooled to −140° C. at a temperature decrease rate of 10° C./min, and then heated to 150° C. at a temperature increase rate of 20° C./min. , an endothermic peak is observed at 40 to 150° C. when the polymer contains a crystalline block segment.

The term "vinyl-based aromatic hydrocarbon" refers to an aromatic hydrocarbon compound having a vinyl group, and specifically includes, for example, styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1 , 3-dimethylstyrene, α-methylstyrene, vinylnaphthalene, vinylanthracene and the like, with styrene being preferred. The vinyl aromatic hydrocarbons may be used alone or in combination of two or more.

"Conjugated diene compound" means a diolefin compound having at least one pair of conjugated double bonds. Specific examples of conjugated diene compounds include 1,3-butadiene, 2-methyl-1,3-butadiene (or isoprene), 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene. , 1,3-hexadiene and the like, with 1,3-butadiene and 2-methyl-1,3-butadiene being preferred. The conjugated diene compounds may be used alone or in combination of two or more.

The hydrogenated ratio in the hydrogenated thermoplastic block copolymer is indicated by "hydrogenation rate". The "hydrogenation rate" of a hydrogenated thermoplastic block copolymer is based on the total ethylenically unsaturated double bonds contained in the block based on the conjugated diene compound, among which hydrogenated saturated Refers to the ratio of ethylenically unsaturated double bonds converted to hydrocarbon bonds. The hydrogenation rate can be measured by an infrared spectrophotometer, a nuclear magnetic resonance apparatus, or the like.

The hydrogenation rate of the hydrogenated thermoplastic block copolymer is preferably 20 to 100%, more preferably 30 to 100%, and particularly preferably 40 to 100%. When the hydrogenation rate of the hydrogenated thermoplastic block copolymer is 20% or more, a styrene-ethylene-butylene-olefin crystal block copolymer and/or an olefin crystal-ethylene/butylene-olefin crystal block copolymer are obtained. The compatibility of the hot melt adhesive is improved and the hot melt adhesive has excellent thermal stability.

As the hydrogenated thermoplastic block copolymer, a hydrogenated styrene triblock copolymer and a hydrogenated styrene diblock copolymer are preferable, and a hydrogenated styrene diblock copolymer is more preferable. The hydrogenated styrenic triblock copolymer and the hydrogenated styrenic diblock copolymer may be used alone or in combination of two or more.

Hydrogenated styrenic triblock copolymers include, for example, SEPS, SEBS, and SEEPS.

SEPS is a block copolymer composed of terminal blocks of styrene blocks and a central block having a mixture of ethylene and propylene structures, that is, a styrene-ethylene/propylene-styrene copolymer.

SEBS is a block copolymer composed of terminal blocks of styrene blocks and a central block having a mixture of ethylene and butylene structures, ie, a styrene-ethylene/butylene-styrene copolymer. Commercially available SEBS products include Kraton G1657, G1650, G1652, G1651 and G1726 (trade names) manufactured by Kraton Polymer Co., Ltd., and DYNARON1321P manufactured by JSR Corporation.

SEEPS is a block copolymer composed of styrene block end blocks and a hydrogenated isoprene/butadiene center block. Commercially available products of SEEPS include Septon 4033, 4044 and 4055 (trade names) manufactured by Kuraray Co., Ltd., and the like.

Hydrogenated styrenic diblock copolymers include, for example, SEB and SEP.

SEB is a block copolymer of a styrene block and a hydrogenated butadiene block, and is a styrene-ethylene-butylene block copolymer.

SEP is a block copolymer of a styrene block and a hydrogenated isoprene block, and is a styrene-ethylene-propylene block copolymer. Commercially available SEPs include Kraton G1701 and G1702 (trade names) manufactured by Kraton Polymer.

The content of the hydrogenated thermoplastic block copolymer in the hot melt adhesive is preferably 10% by mass or more, more preferably 15% by mass or more, and particularly preferably 20% by mass or more in the thermoplastic polymer. The content of the hydrogenated thermoplastic block copolymer in the hot melt adhesive is preferably 95% by mass or less, more preferably 90% by mass or less, and particularly preferably 80% by mass or less in the thermoplastic polymer. When the content of the hydrogenated thermoplastic block copolymer is 10 parts by mass or more, the adhesiveness of the hot melt adhesive is improved. When the content of the hydrogenated thermoplastic block copolymer is 95% by mass or less, the wettability to the adherend is improved, and the adhesiveness of the hot-melt adhesive is improved.

The hot melt adhesive may contain an olefin crystal copolymer as the thermoplastic polymer. An olefin crystal copolymer is a copolymer containing an olefin as a monomer component and having a crystalline segment. Such olefin crystalline copolymers are not particularly limited, but ethylene-propylene crystalline copolymers (ethylene-propylene copolymers having crystalline segments) and ethylene - octene crystalline copolymers (ethylene-octene copolymers with crystalline segments) are preferred, ethylene-propylene crystalline copolymers (ethylene-propylene copolymers with crystalline segments) and ethylene-octene block crystalline copolymers Coalescence (ethylene-octene copolymer with crystalline segments) is more preferred. The olefin is not particularly limited, and examples include ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene and 1-decene. mentioned. Olefin crystalline copolymers are sometimes referred to as "olefin crystalline copolymers."

Whether or not it has a crystalline segment is determined by heating and melting the copolymer, cooling it to −140° C. at a temperature decrease rate of 10° C./min, and then heating it to 150° C. at a temperature increase rate of 20° C./min. When the copolymer contains a crystalline segment, an endothermic peak is observed at 40 to 150°C.

The content of the olefin crystal copolymer in the thermoplastic polymer is preferably 25% by mass or more, more preferably 30% by mass or more, and particularly preferably 35% by mass or more. When the content of the olefin crystal copolymer is 25% by mass or more, the wettability to the adherend is improved, and the adhesiveness of the hot-melt adhesive is improved. When the content of the olefinic resin is 80% by mass or less, the adhesiveness of the hot-melt adhesive is improved.

As commercial products of olefin crystal copolymers, Infuse 9817 (trade name) manufactured by Dow Chemical Co. [ethylene-octene block copolymer obtained by polymerization with a metallocene catalyst (olefin crystal copolymer)], Exxon • Vistamax 6202 (trade name) (ethylene-propylene copolymer obtained by polymerization with a metallocene catalyst) manufactured by Mobil Corporation.

Hot melt adhesives contain tackifiers. The tackifier is not particularly limited as long as it is commonly used in hot-melt adhesives and the desired hot-melt adhesive of the present invention can be obtained.

Tackifiers are additives that impart tackiness to thermoplastic polymers. Tackifiers include, for example, natural rosin, modified rosin, hydrogenated rosin, glycerol ester of natural rosin, glycerol ester of modified rosin, pentaerythritol ester of natural rosin, pentaerythritol ester of modified rosin, and pentaerythritol of hydrogenated rosin. Esters, Copolymers of Natural Terpenes, Three-Dimensional Polymers of Natural Terpenes, Hydrogenated Derivatives of Copolymers of Hydrogenated Terpenes, Polyterpene Resins, Hydrogenated Derivatives of Phenolic Modified Terpene Resins, Aliphatic Petroleum Hydrocarbon Resins, Aliphatic Petroleum Hydrocarbon Resins hydrogenated derivatives of aromatic petroleum hydrocarbon resins, hydrogenated derivatives of aromatic petroleum hydrocarbon resins, cycloaliphatic petroleum hydrocarbon resins, hydrogenated derivatives of cycloaliphatic petroleum hydrocarbon resins, etc., and hydrogenated terpene hydrogenated derivatives of phenolic modified terpene resins, hydrogenated derivatives of aliphatic petroleum hydrocarbon resins, hydrogenated derivatives of aromatic petroleum hydrocarbon resins, hydrogenated derivatives of cycloaliphatic petroleum hydrocarbon resins is preferred. In addition, a tackifier may be used independently or 2 or more types may be used together. The tackifier may contain a liquid tackifier that is liquid at 23° C. and ¹ atm. The inclusion of a liquid tackifier improves the low-temperature tackiness of the hot-melt adhesive. Note that a liquid is one of aggregates represented by substances, and has a certain volume but does not have a certain shape.

A commercial item can be used as a tackifier. Examples of such commercial products include ESCOREZ5400, ESCOREZ5600 and ESCOREZ231C (trade names) manufactured by Exxon Corporation, Clearon P100 and Clearon K100 (trade names) manufactured by Yasuhara Chemical Co., Ltd., Alcon P100 and Alcon M100 (trade names) manufactured by Arakawa Chemical Co., Ltd. name), Idemitsu Petrochemical Co. Imave P100 and Imave S100 (trade names), Yasuhara Chemical Co. Clearon K4090 and Clearon K4100 (trade names), Eastman Chemical Co. Ligalite R7100 (trade name), and the like. A commercial item can be used as a liquid tackifier. Examples of such commercial products include Ligalite R-1010 and Ligalite C-8010 (trade names) manufactured by Eastman Chemical Company.

The content of the tackifier in the hot melt adhesive is preferably 100 to 600 parts by mass, more preferably 100 to 500 parts by mass, more preferably 250 to 500 parts by mass, with respect to 100 parts by mass of the thermoplastic polymer. ~450 parts by weight is particularly preferred. When the content of the tackifier in the hot-melt adhesive is 100 parts by mass or more, the adhesiveness of the hot-melt adhesive is improved. When the tackifier is 600 parts by mass or less, the adhesiveness of the hot-melt adhesive is improved.
The content of the liquid tackifier in the tackifier is preferably 5 to 80% by mass, more preferably 5 to 60% by mass, more preferably 5 to 50% by mass, more preferably 8 to 40% by mass, 8 to 20% by weight is particularly preferred. When the content of the liquid tackifier is 5% by mass or more, the adhesiveness of the hot-melt adhesive is improved. When the content of the liquid tackifier is 80% by mass or less, the releasability of the hot-melt adhesive is improved.

The hot melt adhesive may contain a plasticizer. Plasticizers are blended for the purpose of improving coatability by lowering the melt viscosity during coating of hot melt adhesives, imparting flexibility to hot melt adhesives, or improving wettability to adherends. .

Any plasticizer may be used as long as it is compatible with the thermoplastic polymer and does not impair the effects of the hot-melt adhesive.

Plasticizers include, for example, naphthenic oils, paraffinic oils (e.g. cycloparaffinic oils), mineral oils, phthalates, adipates, olefin oligomers (e.g. polypropylene, polybutene and hydrogenated polyisoprene oligomers), polybutene. , polyisoprene, hydrogenated polyisoprene, polybutadiene, benzoic acid esters, animal oils, vegetable oils (eg, castor oil, soybean oil), oil derivatives, glycerol esters of fatty acids, polyesters, polyethers, lactic acid derivatives, and the like. The plasticizers may be used alone or in combination of two or more. In particular, paraffinic and naphthenic oils are preferred, and paraffinic and naphthenic process oils are preferred.

A commercial item can be used as a plasticizer. Examples of such commercial products include White Oil Broom 350 (trade name) manufactured by Kukdong Oil & Chem, Diana Fresia PS-32 (trade name) manufactured by Idemitsu Kosan Co., Ltd., Diana Process Oil PW-90 (trade name) and Daphne -Oil KP-68 (trade name), Enerper M1930 (trade name) manufactured by BP Chemicals, Kaydol (trade name) manufactured by Crompton, Primol 352 (trade name) manufactured by Exxon, Process Oil NS manufactured by Idemitsu Kosan Co., Ltd.- 100 (trade name), Petro China's trade name "KN4010", and the like.

The blending amount of the plasticizer is preferably 10 parts by mass or more, more preferably 150 parts by mass, and particularly preferably 200 parts by mass or more based on 100 parts by mass of the thermoplastic polymer. The amount of the plasticizer compounded is preferably 400 parts by mass or less, more preferably 350 parts by mass or less, and particularly preferably 300 parts by mass or less with respect to 100 parts by mass of the thermoplastic polymer. When the content of the plasticizer is 10 parts by mass or more, the penetration of the hot-melt adhesive into the nonwoven fabric constituting the tape substrate is sufficient, and adhesive residue is produced when the adhesive tape is peeled off from the adherend. It can be peeled off without damage. When the content of the plasticizer is 400 parts by mass or less, the cohesive force of the hot-melt adhesive is improved, thereby improving the adhesiveness and allowing the hot-melt adhesive to be releasably adhered to the adherend.

The hot melt adhesive may further contain various additives as required. Such additives include, for example, additional polymers, waxes and particulate fillers.

Stabilizers are used to prevent molecular weight reduction, gelation, coloration, or odor generation in hot-melt adhesives, and to improve the stability of hot-melt adhesives when heated. It is not particularly limited as long as it does not exhibit the effects of the melt adhesive. Stabilizers include, for example, antioxidants, ultraviolet absorbers, heat stabilizers, and the like. The stabilizers may be used alone or in combination of two or more.

Examples of antioxidants include hindered phenol-based antioxidants, phenol-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants. Examples of UV absorbers include benzotriazole-based UV absorbers and benzophenone-based UV absorbers. Examples of heat stabilizers include lactone-based heat stabilizers. A commercial item can be used as a stabilizer. Examples of such commercial products include Sumilizer GM (trade name), Sumilizer TPD (trade name) and Sumilizer TPS (trade name) manufactured by Sumitomo Chemical Co., Ltd., and Irganox 1010 (trade name) manufactured by Ciba Specialty Chemicals. ), Irganox HP2225FF (trade name), Irgafos 168 (trade name), Irganox 1520 (trade name) and Tinuvin P, JF77 (trade name) manufactured by Johoku Kagaku Co., Ltd., Tominox TT (trade name) manufactured by API Corporation. ) and the like.

The wax is a wax commonly used in hot melt adhesives, and is not particularly limited as long as it does not impair the effects of the hot melt adhesive. Examples of waxes include synthetic waxes such as Fischer-Tropsch wax and polyolefin wax (polyethylene wax and polypropylene wax); petroleum waxes such as paraffin wax and microcrystalline wax; and natural waxes such as castor wax.

The particulate filler is generally used in hot melt adhesives, and is not particularly limited as long as it does not impair the effects of the hot melt adhesive. Examples of fine particle fillers include mica, calcium carbonate, kaolin, talc, titanium oxide, diatomaceous earth, urea-based resins, styrene beads, calcined clay, and starch. Spherical particles are preferred for the particulate filler.

Hot-melt adhesives can be produced by mixing a thermoplastic polymer, a tackifier, a plasticizer, and optional additives while heating and melting them in a known manner.

In addition to the hot melt adhesive (1), 100 parts by mass of a thermoplastic polymer containing 25% by mass or more of an olefin crystal copolymer, 100 to 600 parts by mass of a tackifier, and 10 to 400 parts by mass of a plasticizer. It may be a hot melt adhesive (2) containing

The hot melt adhesive (2) has the same structure as the hot melt adhesive (1) except that the thermoplastic polymer contains 25% by mass or more of the olefin crystal copolymer. , and the hot-melt adhesive (1) will not be described. Further, since the olefin crystal copolymer is the same as the copolymer described above, the explanation thereof is omitted.

The content of the olefin crystal copolymer in the thermoplastic polymer is preferably 25% by mass or more, more preferably 30% by mass or more, and particularly preferably 50% by mass or more. The content of the olefin crystal copolymer in the thermoplastic polymer is preferably 85% by mass or less, more preferably 80% by mass or less, and particularly preferably 75% by mass or less. When the content of the olefin crystal copolymer is 25% by mass or more, it is possible to effectively suppress the adhesive residue of the hot-melt adhesive. When the content of the olefin crystal copolymer is 85% by mass or less, the adhesiveness of the hot-melt adhesive is improved.

The hot melt adhesive (2) may contain 25% by mass or more of an olefin crystal copolymer as an essential component in the thermoplastic polymer, and is a styrene-ethylene-butylene-olefin crystal block copolymer and/or The olefin crystal-ethylene/butylene-olefin crystal block copolymer may be contained in the thermoplastic polymer.

The total amount of the styrene-ethylene-butylene-olefin crystal block copolymer and the olefin crystal-ethylene/butylene-olefin crystal block copolymer in the thermoplastic polymer is preferably at least 25% by mass, more preferably at least 30% by mass. 50% by mass or more is particularly preferred. The total amount of the styrene-ethylene-butylene-olefin crystal block copolymer and the olefin crystal-ethylene/butylene-olefin crystal block copolymer in the thermoplastic polymer is preferably 85% by mass or less, more preferably 80% by mass or less, 75% by mass or less is particularly preferred. When the total amount of the styrene-ethylene-butylene-olefin crystal block copolymer and the olefin crystal-ethylene/butylene-olefin crystal block copolymer is 25% by mass or more, it is effective in preventing adhesive residue from occurring in the hot-melt adhesive. can be suppressed to When the total amount of the styrene-ethylene-butylene-olefin crystal block copolymer and the olefin crystal-ethylene/butylene-olefin crystal block copolymer is 85% by mass or less, the coatability of the hot melt adhesive is improved.

When the thermoplastic polymer contains either a styrene-ethylene-butylene-olefin crystal block copolymer or an olefin crystal-ethylene/butylene-olefin crystal block copolymer, the block in the thermoplastic polymer The content of the copolymer is preferably 25% by mass or more, more preferably 30% by mass or more, and particularly preferably 50% by mass or more. The content of the block copolymer in the thermoplastic polymer is preferably 85% by mass or less, more preferably 80% by mass or less, and particularly preferably 75% by mass or less. Since the reason is the same as the above, it is omitted.

Hot melt adhesives are widely used in a variety of applications, including pressure sensitive adhesives (eg, releasable and permanent). Hot melt adhesives are widely used in paper processing, book binding, adhesives for attaching insert pages to printed materials (e.g. magazines), assembly of various components [e.g. filters, laminates, wood edges (i.e. edgebanding)]. Adhesives, adhesives used for packages (e.g., cases, cartons, trays, etc.), adhesives used for tapes and labels (including bottle labels), and adhesives used for disposable items. can. Hot melt adhesives can be applied to a variety of substrates. Substrates include, for example, films [e.g., polyolefin films (e.g., polyethylene films and polypropylene films)], release liners, porous substrates, cellulose substrates, sheets (e.g., paper and fiber sheets), paper products, woven Fabric webs, nonwoven webs, fibers (eg, synthetic resin fibers and cellulose fibers), tape backings, and the like. Hot melt adhesives have many applications and are useful in assembly. Hot melt adhesives are used, for example, in disposable articles [e.g. medical dressings (e.g. wound care products), bandages, processed meat products], parts of articles [e.g. thin fabrics (e.g. packaging thin fabrics), layers, and woven and non-woven web layers], elastic materials and their assembly. Hot melt adhesives can be applied to various uses of these articles (ie, assembly, elastic attachment and core). Hot melt adhesives are suitable for use on a variety of fibers (e.g., natural cellulosic fibers such as wood pulp, cotton, silk, and wool; synthetic fibers such as nylon, rayon, polyester, acrylic, polypropylene, polyethylene, polyvinyl chloride, polyurethane, and glass; It can be used in substrates formed from recycled fibers, and fibers in which they are combined. Hot-melt adhesives can be easily applied to the tape substrate using a hot-melt coating machine and do not require a drying process, so the production equipment can be made compact and the adhesive tape can be efficiently processed. can be manufactured well.

The method of applying the hot-melt adhesive to a member such as a tape substrate is not particularly limited, and may be either contact application or non-contact application. "Contact application" refers to the application method in which the ejector is brought into contact with the member when applying the hot melt adhesive. A non-contact application method. Examples of contact coating methods include slot coater coating and roll coater coating. Examples of non-contact coating methods include spiral coating that can be applied in a spiral shape, omega coating that can be applied in a wave pattern, control seam coating, slot spray coating that can be applied in a plane, curtain spray coating, and point coating. Examples include dot coating that can be processed.

The above hot-melt adhesive is suitable for use in the production of pressure-sensitive adhesive tapes. The hot-melt adhesive has excellent permeability between the fibers of the nonwoven fabric, and is therefore suitable for use in the production of pressure-sensitive adhesive tapes in which the tape substrate is made of nonwoven fabric.

The hot-melt adhesive is difficult to harden when applied onto the tape base material, sufficiently permeates between the fibers of the nonwoven fabric constituting the tape base material, and firmly integrates with the tape base material. At the same time, the fibers of the non-woven fabric constituting the tape base material are integrated with each other to reinforce the fiber layer of the hot-melt adhesive-applied portion, thereby improving the mechanical strength. Therefore, when the adhesive tape is peeled off or removed from the adherend after use, the tape substrate may be damaged or the hot melt adhesive may be detached from the tape substrate. There is no so-called adhesive residue left behind. The application of the hot-melt adhesive to the tape base material may be performed by applying the hot-melt adhesive directly to the tape base material in a known manner, or by applying a release treatment to a film that has been subjected to a release treatment on one side. The hot melt adhesive may be applied to the tape substrate by applying the hot melt adhesive to the surface and then transferring the hot melt adhesive onto the tape substrate.

The basis weight of the tape base material including the non-woven fabric constituting the adhesive tape is preferably 5 to 30 g/m ² .

In the above description, the tape substrate of the adhesive tape is formed of non-woven fabric, and the hot-melt adhesive is used to form an adhesive layer on the surface of the tape substrate. The member to be machined is not limited to the tape substrate, and may be another member made of nonwoven fabric.

Since the hot-melt adhesive of the present invention has the structure as described above, it sufficiently permeates between the fibers of the nonwoven fabric and other substrates when applied to the nonwoven fabric, and after cooling, It is difficult to separate from the adhesive, has excellent adhesion to the adherend during use, and is excellent in coating suitability.

4 is a graph showing the results of dynamic viscoelasticity measurement of hot melt adhesives.

EXAMPLES The present invention will be described in more detail below using examples, but the present invention is not limited to these.

Compounds used in Examples and Comparative Examples are described.

[Thermoplastic polymer]
・Styrene-ethylene-butylene-olefin crystal block copolymer (SEBC, trade name “DYNARON4600P” manufactured by JSR, styrene content: 20% by mass, melt flow rate: 5.5 g/10 minutes)
・Olefin crystal-ethylene/butylene-olefin crystal block copolymer (CEBC, trade name “DYNARON6200P” manufactured by JSR, melt flow rate: 2.5 g/10 minutes)
・Styrene-isoprene-styrene block copolymer (SIS, trade name “D1161JP” manufactured by Kraton Polymer Co., styrene content: 15% by mass)

(Hydrogenated thermoplastic block copolymer)
・ Styrene-ethylene-butadiene-styrene elastomer 1 (SEBS1, trade name “Kraton G1726” manufactured by Kraton Polymer Co., Ltd., having no crystalline block segment, styrene content: 30% by mass, hydrogenation rate: 100%)
・Styrene-ethylene-butadiene-styrene elastomer 2 (SEBS2, trade name “DYNARON1321P” manufactured by JSR, having no crystalline block segment, styrene content: 10% by mass, hydrogenation rate: 100%)
・Styrene-ethylene-butadiene-styrene elastomer 3 (SEBS3, trade name “Kraton G1652” manufactured by Kraton Polymer Co., Ltd., having no crystalline block segment, styrene content: 30% by mass, hydrogenation rate: 100%)

(Olefin crystal copolymer)
・Olefin crystal copolymer 1 (ethylene-octene block copolymer, polymerized with a metallocene catalyst, trade name “Infuse 9817” manufactured by Dow Chemical Company, having a crystalline segment)
・Olefin crystal copolymer 2 (ethylene-propylene copolymer, polymerized with a metallocene catalyst, product name “Vistamax 6202” manufactured by Exxon-Mobil, having a crystalline segment)

(Olefin-based copolymer)
- Ethylene-octene copolymer 1 (manufactured by DOW Chemical, trade name "AFFINITY GA1875", MFR: 1250 g / 10 minutes, no crystalline segment)
Ethylene-octene copolymer 2 (trade name “ENGAGE 8407” manufactured by DOW Chemical, MFR: 30 g/10 min, no crystalline segment)

[Tackifier]
Hydrogenated petroleum resin 1 [Exxon trade name “ESCOREZ5400”, solid at 23 ° C. and 1.01325 × 10 ⁵ Pa (1 atm)]
Hydrogenated petroleum resin 2 [Exxon trade name “ECR179EX”, solid at 23 ° C. and 1.01325 × 10 ⁵ Pa (1 atm)]
Hydrogenated petroleum resin 3 [trade name “Arcon P-100” manufactured by Arakawa Chemical Co., Ltd., solid at 23 ° C. and 1.01325 × 10 ⁵ Pa (1 atm)]
Hydrogenated petroleum resin 4 [Eastman Chemical Co., Ltd. trade name “Ligalite C-8010”, liquid at 23 ° C. and 1.01325 × 10 ⁵ Pa (1 atm)]

[Plasticizer]
・Naphthenic process oil (trade name “KN4010” manufactured by Petro China)

[Stabilizer]
・ Hindered phenol-based antioxidant (trade name “Irganox 1010” manufactured by Ciba Specialty Chemicals)
・Benzotriazole-based UV absorber (trade name “Tinuvin P” manufactured by Ciba Specialty Chemicals)

(Examples 1 to 16, Comparative Examples 1 to 5)
The above-described thermoplastic polymer, tackifier, plasticizer, and stabilizer are melted and kneaded at 170°C in the amounts shown in Tables 1 and 2 (unit: parts by mass) to form a hot melt adhesive. manufactured.

The highest temperature at which tan δ (loss elastic modulus G″/storage elastic modulus G′) is 1, measured by a temperature rising method and a cooling method at a frequency of 1 Hz, for the resulting hot melt adhesive. T ₁ and T ₂ , and the peak value of tan δ (loss elastic modulus G″/storage elastic modulus G′) measured by the temperature rising method at a frequency of 1 Hz by dynamic viscoelasticity measurement are measured as described above, The results are shown in Tables 1 and 2.

The resulting hot-melt adhesive was measured for permeability to non-woven fabric, adhesiveness (probe tack), 90° peeling adhesive strength and releasability in the following manner, and the results are shown in Tables 1 and 2.

[Penetration into nonwoven fabric]
Using a slot coater (manufactured by Suntool Co., Ltd.), a hot-melt adhesive was applied to a thickness of 100 μm on the release-treated surface of a release paper having one surface subjected to release treatment. On the other hand, two nonwoven fabrics having a basis weight of 13 g/m ² were prepared, and the two nonwoven fabrics were laminated to form a laminate.

Next, a release paper is superimposed on the surface of the laminate so that the hot melt adhesive is on the laminate side, and after the hot melt adhesive is transferred to the laminate side, the release paper is peeled off from the laminate and removed, A sample was prepared by cooling the hot melt adhesive to room temperature. The state when the two nonwoven fabrics constituting the sample were separated from each other by hand from the interface was evaluated based on the following criteria.

A. The hot-melt adhesive sufficiently permeated the two nonwoven fabrics and the two nonwoven fabrics could not be peeled off.
B: The hot-melt adhesive penetrated to the surface of the second nonwoven fabric, and when the nonwoven fabrics were separated from each other, the surface of the second nonwoven fabric was broken.
C. The hot-melt adhesive sufficiently permeated the first nonwoven fabric, but when the nonwoven fabrics were peeled off, the nonwoven fabrics could be separated without breaking the second nonwoven fabric. .
D... The hot-melt adhesive did not sufficiently permeate the first nonwoven fabric.

[Adhesion (probe tack)]
A slot coater (manufactured by Suntool Co., Ltd.) was used to coat a polyethylene terephthalate film (thickness of 50 μm) with a hot-melt adhesive in a thickness of 50 μm and a width of 15 mm. Next, on the hot-melt adhesive, a release paper having one surface subjected to a release treatment was superposed so that the release-treated surface faced the hot-melt adhesive, and the pressure of its own weight (0.25 kgf) was applied. / cm) to prepare a sample.

Using an NS probe tack tester (manufactured by Nichiban Co., Ltd.), the resulting sample was tested for probe tack on a hot melt adhesive on a polyethylene terephthalate film under the conditions of a load of 10 g/cm ² , a dwell time of 1 second and a speed of 1 cm/second. was measured. It was evaluated based on the following criteria. The measurement temperature was 23°C. Probe tack is an indicator of adhesiveness.
A: 1000 gf or more.
B: 500 gf or more and less than 1000 gf.
C... less than 500 gf.
The probe tack was measured in the same manner as above except that the measurement temperature was 10°C. It was evaluated based on the following criteria.
A: 1000 gf or more.
B: 500 gf or more and less than 1000 gf.
C... less than 500 gf.

[90° Peel Adhesion and Peelability]
Using a slot coater (manufactured by Suntool Co., Ltd.), a hot-melt adhesive was applied to a thickness of 100 μm on the release-treated surface of a release paper having one surface subjected to release treatment. Next, a nonwoven fabric having a basis weight of 20 g/m ² is prepared, and release paper is superimposed on the surface of this nonwoven fabric so that the hot melt adhesive is on the nonwoven fabric side, and the hot melt adhesive is transferred to the nonwoven fabric side. After that, the release paper was peeled off and removed from the nonwoven fabric, and the hot-melt adhesive was cooled to room temperature to prepare and wind an adhesive tape.

The obtained pressure-sensitive adhesive tape was measured for 90° peeling adhesion to a polyethylene plate in accordance with JIS Z0237, and evaluated according to the following criteria.
A: 10 N/25 mm or more.
B...5 N/25 mm or more and less than 10 N/25 mm.
C: 2 N/25 mm or more and less than 5 N/25 mm.
D... It was less than 2N/25mm.

After measuring the 90° peeling adhesive strength, the surface of the polyethylene plate was visually observed and evaluated according to the following criteria.
A: No hot-melt adhesive remained on the surface of the polyethylene plate.
B: Only a small amount of the hot-melt adhesive remained on the surface of the polyethylene plate.
C: A small amount of hot-melt adhesive and non-woven fabric remained on the surface of the polyethylene plate.
D: A large amount of hot-melt adhesive and non-woven fabric remained on the surface of the polyethylene plate.

(Cross reference to related applications)
This application claims priority based on Japanese Patent Application No. 2017-128978 filed on June 30, 2017, and the disclosure of this application is incorporated herein by reference in its entirety. .

The hot melt adhesive of the present invention sufficiently permeates between fibers of the nonwoven fabric and other substrates when applied to the nonwoven fabric, and is less likely to be peeled off from the substrate after cooling. It has excellent peelability from adherends and excellent coating suitability. Therefore, the hot-melt adhesive of the present invention can be applied to articles for various uses and their assembly.

G1 tan δ (loss elastic modulus G″/storage elastic modulus G′) curve measured by dynamic viscoelasticity measurement at a frequency of 1 Hz by a heating method G2 measured by a dynamic viscoelasticity measurement by a temperature decreasing method at a frequency of 1 Hz tan δ (loss elastic modulus G″/storage elastic modulus G′) curve H Peak value of tan δ measured by dynamic viscoelasticity measurement at a frequency of 1 Hz by a heating method T ₁ Dynamic viscoelasticity measurement at a frequency of 1 Hz The highest temperature at which tan δ (loss elastic modulus G″/storage elastic modulus G′) measured by the method is 1 T ₂ tan δ (loss elastic modulus The highest temperature at which G″/storage modulus G′) becomes 1

Claims (4)

The highest temperature at which tan δ (loss elastic modulus G″/storage elastic modulus G′) measured by the heating method at a frequency of 1 Hz by dynamic viscoelasticity measurement is 1, and the temperature is lowered at a frequency of 1 Hz by dynamic viscoelasticity measurement. The difference from the highest temperature at which tan δ (loss elastic modulus G″/storage elastic modulus G′) measured by the method is 1 is 6 ° C. or more, and the temperature is increased at a frequency of 1 Hz by dynamic viscoelasticity measurement. A hot melt adhesive having a tan δ peak value of 1.5 or more as measured by
A styrene-ethylene-butylene-olefin crystal block copolymer having a styrene component content of 15 to 35% by mass and a melt flow rate of 1 to 20 g/10 min, and/or a melt flow rate of 0.5 to 100 parts by mass of a thermoplastic polymer containing 25% by mass or more of an olefin crystal-ethylene/butylene-olefin crystal block copolymer of 10 g/10 min;
250 to 450 parts by mass of a tackifier containing a hydrogenated petroleum resin;
150 to 300 parts by mass of a plasticizer,
When the total amount of the styrene-ethylene-butylene-olefin crystal block copolymer and the olefin crystal-ethylene/butylene-olefin crystal block copolymer in the thermoplastic polymer is less than 100% by mass, the thermoplastic polymer is a hydrogenated thermoplastic block copolymer containing at least one of a hydrogenated styrene triblock copolymer and a hydrogenated styrene diblock copolymer, or a styrene-isoprene-styrene block copolymer A hot melt adhesive comprising: The highest temperature at which tan δ (loss elastic modulus G″/storage elastic modulus G′) measured by the heating method at a frequency of 1 Hz by dynamic viscoelasticity measurement is 1, and the temperature is lowered at a frequency of 1 Hz by dynamic viscoelasticity measurement. 2. The hot melt adhesive according to claim 1, wherein the difference from the highest temperature at which tan δ (loss elastic modulus G″/storage elastic modulus G′) becomes 1 measured by the method is 15° C. or more. agent. 2. The hot melt adhesive according to claim 1, wherein the thermoplastic polymer contains 10% by mass or more of the hydrogenated thermoplastic block copolymer. The highest temperature at which tan δ (loss elastic modulus G″/storage elastic modulus G′) measured by the heating method at a frequency of 1 Hz by dynamic viscoelasticity measurement is 1, and the temperature is lowered at a frequency of 1 Hz by dynamic viscoelasticity measurement. The difference from the highest temperature at which tan δ (loss elastic modulus G″/storage elastic modulus G′) measured by the method is 1 is 6 ° C. or more, and the temperature is increased at a frequency of 1 Hz by dynamic viscoelasticity measurement. A hot melt adhesive having a tan δ peak value of 1.5 or more as measured by
100 parts by mass of a thermoplastic polymer containing 50% by mass or more of an olefin crystal copolymer that is an ethylene-propylene crystal copolymer and/or an ethylene-octene crystal copolymer;
250 to 450 parts by mass of a tackifier containing a hydrogenated petroleum resin ;
150 to 300 parts by mass of a plasticizer ,
When the total amount of the olefin crystal copolymer in the thermoplastic polymer is less than 100% by mass, the thermoplastic polymer is a hydrogenated styrene triblock copolymer and a hydrogenated styrene diblock copolymer. A hot melt adhesive comprising a hydrogenated thermoplastic block copolymer containing at least one of coalescence .

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