Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L53/00—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
  • C08L53/02—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers of vinyl-aromatic monomers and conjugated dienes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
  • C09J11/08—Macromolecular additives
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J125/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Adhesives based on derivatives of such polymers
  • C09J125/02—Homopolymers or copolymers of hydrocarbons
  • C09J125/04—Homopolymers or copolymers of styrene
  • C09J125/08—Copolymers of styrene
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J153/00—Adhesives based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers

Definitions

• the present invention relates to hot melt compositions.
• absorbent articles containing sanitary materials such as disposable diapers and sanitary napkins have been widely used. These absorbent articles use a laminate made of stretchable members to prevent them from slipping off when worn.
• Rubber threads made of natural rubber or synthetic polymers are known as elastic members used in laminates. Since rubber thread exhibits good stress when stretched, it is effective in preventing absorbent articles from slipping off when worn.
• thermoplastic elastomer composition used as a stretchable member of the laminate used in the absorbent article.
• a hot melt stretchable adhesive composition has been proposed as a thermoplastic elastomer composition used in the stretchable film.
• Patent Document 1 improvement in extensibility has not been sufficiently studied, and there is room for improvement.
• the elastic members used in the sanitary materials are required to have sufficient extensibility.
• Patent Document 1 suppression of a decrease in stretch recovery properties is not sufficiently studied.
• a sanitary material such as a paper diaper
• the elastic member used in the sanitary material is stretched. Therefore, the elastic member is required to suppress deterioration in elastic recovery even when held in an expanded state.
• Patent Document 1 describes that a considerable amount of tackifier is blended into the hot melt composition ([0007] of Patent Document 1, Table 2 (hydrogenated petroleum resin)), and the elastic member becomes hard and has sufficient expansion and contraction. The problem is that recovery cannot be demonstrated.
• the hot melt composition forming the elastic member is required to have excellent coating suitability. If the hot melt composition forming the stretchable member has a high melt viscosity or a high softening point, it is necessary to mold the stretchable hot melt composition using an extrusion device, which causes a problem of reduced productivity. . Therefore, the stretchable hot melt composition is required to have coating suitability (meltability) that allows it to be coated with a general-purpose hot melt coating device.
• the present invention provides a hot melt composition that can form a stretchable member with excellent stretchability, stretch recovery properties, and stress maintenance properties during stretching at high temperatures, and has excellent coating suitability.
• the purpose is to provide.
• thermoplastic resin (A) has a styrene content.
• the above hot melt composition contains 40 to 65% by mass of hydrogenated styrenic block copolymer (A1), and has a stress retention rate of 50% or more when measured under specific conditions of the hot melt composition.
• the inventors have discovered that the object can be achieved and have completed the present invention.
• a hot melt composition comprising a thermoplastic resin (A) and a plasticizer (B),
• the thermoplastic resin (A) contains a hydrogenated styrenic block copolymer (A1) with a styrene content of 40 to 65% by mass,
• the hot melt composition has a stress retention rate of 50% or more after being held in a 2-fold stretched state for 1 hour at a temperature of 40°C.
• a hot melt composition characterized by: 2. Item 2. The hot melt composition according to Item 1, wherein the content of the hydrogenated styrenic block copolymer (A1) is 25 to 40% by mass, based on 100% by mass of the hot melt composition. 3.
• the hot melt composition according to Item 1 or 2 wherein the hydrogenated styrenic block copolymer (A1) is a hydrogenated product of a block copolymer containing styrene units and butadiene units. 4.
• Item 4 The hot melt composition according to any one of Items 1 to 3, wherein the hydrogenated styrenic block copolymer (A1) is a styrene-ethylene-butylene/styrene-styrene copolymer. 5.
• Item 5 The hot melt composition according to any one of Items 1 to 4, which has a melt viscosity of 5,000 to 35,000 mPa ⁇ s at 180° C., as measured using a Brookfield RVT viscometer (spindle No.
• the hot melt composition of the present invention can form a stretchable member with excellent stretchability, stretch recovery properties, and stress maintenance properties during stretch at high temperatures, and has excellent coating suitability.
• the hot melt composition of the present invention is a hot melt composition containing a thermoplastic resin (A) and a plasticizer (B), wherein the thermoplastic resin (A) has a styrene content.
• the stress maintenance rate of the hot melt composition containing 40 to 65% by mass of a hydrogenated styrenic block copolymer (A1) after being held in a 2-fold stretched state for 1 hour at a temperature of 40°C is It is 50% or more.
• the hot melt composition of the present invention can form an elastic member by containing the above (A) and (B), and in particular, the thermoplastic resin (A) has a styrene content of 40 to 65% by mass.
• the hot melt composition By containing the hydrogenated styrenic block copolymer (A1) and having the above-mentioned stress retention rate of the hot melt composition of 50% or more, the hot melt composition has good extensibility, stretch recovery, and stress maintenance during stretching at high temperatures. It is possible to form a stretchable member with excellent properties and exhibit excellent coating suitability. That is, the hot melt composition of the present invention has all the above-mentioned configurations, thereby making it possible to form a stretchable member with excellent stretchability, stretch recovery properties, and stress maintenance properties during stretch at high temperatures, and It has excellent coating suitability, making it possible to combine all of these properties.
• high temperature means a temperature comparable to human body temperature, about 35 to 42 degrees Celsius, preferably about 35.5 to 41.5 degrees Celsius, more preferably about 36 to 41 degrees Celsius, especially Preferably it means a temperature of 40°C.
• warming means bringing the temperature to the above range.
• room temperature means 23°C.
• the stress retention rate of the hot melt composition of the present invention after being held in a 2-fold stretched state for 1 hour at a temperature of 40°C is 50% or more. If the stress retention rate is less than 50%, the stress retention during elongation at high temperatures will not be sufficient.
• the stress maintenance rate is preferably 60% or more, more preferably 70% or more, and even more preferably 75% or more. Further, the upper limit of the stress maintenance rate is preferably as high as possible, and may be 100% or less, 90% or less, or 85% or less.
• the stress maintenance rate of the hot melt composition is evaluated in detail by the method described in the Examples below.
• the hot melt composition of the present invention preferably has a melt viscosity at 180° C. of 3,000 to 50,000 mPa ⁇ s, more preferably 5,000 to 35,000 mPa ⁇ s, and even more preferably 7,000 to 28,000 mPa ⁇ s.
• the coating suitability of the hot melt composition is further improved.
• the melt viscosity of the hot melt composition at 180° C. is evaluated by the method described in Examples below.
• thermoplastic resin (A) contains a hydrogenated styrenic block copolymer (A1) having a styrene content of 40 to 65% by mass.
• the styrenic block copolymer (A1) is not particularly limited as long as it is a hydrogenated styrenic block copolymer with a styrene content of 40 to 65% by mass.
• a hydrogenated product of a block copolymer containing styrene units and butadiene units can be suitably used.
• the styrene block copolymer (A1) includes styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-butylene-butadiene-styrene copolymer (SBBS), styrene-ethylene-butylene /Styrene-styrene copolymer (SEB/S-S), styrene-ethylene-propylene-styrene copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene copolymer (SEEPS), styrene-ethylene-butylene -Olefin crystal copolymer (SEBC) and the like.
• SEBS styrene-ethylene-butylene-styrene copolymer
• SBBS styrene-butylene-butadiene-styrene copolymer
• SEBS styrene-ethylene-butylene-styrene copolymer
• styrene-butylene-butadiene-styrene copolymer are superior in extensibility, stretch recovery, and stress retention during stretching at high temperatures.
• SBBS Polymer
• SEB/S-S styrene-ethylene-butylene/styrene-styrene copolymer
• SEPS styrene-ethylene-propylene-styrene copolymer
• SEBS polymer
• SEB/S-S polymer
• SEB/S-S polymer
• SEB/S-S polymer
• SEB/S-S polymer
• SEB/S-S polymer
• SEB/S-S styrene-ethylene-butylene/styrene-styrene copolymer
• SEB/S-S styrene-ethylene-butylene/styrene-styrene copolymer
• SEB/S-S styrene-ethylene-butylene/styrene-styrene copolymer
• the above styrenic block copolymer (A1) may be used alone or in combination of two or more.
• SEB/S-S styrene-ethylene-butylene/styrene-styrene copolymer
• SEB/S-S styrene-ethylene-butylene/styrene-styrene copolymer
• a hot melt composition containing a styrene-ethylene-butylene/styrene-styrene copolymer can have both good extensibility and good stretch recovery.
• the increase in melt viscosity at low temperatures is suppressed.
• the coating suitability of the coating can be further improved.
• the method for preparing the styrene-ethylene-butylene/styrene-styrene copolymer is not particularly limited, and includes, for example, the method described in US Pat. No. 7,169,848.
• styrene-ethylene-butylene/styrene-styrene copolymer commercially available products can be used. Commercially available products include A1537, A1536, and A1535 manufactured by Clayton Polymer Co., Ltd.
• the styrene content of the styrenic block copolymer (A1) is 40 to 65% by mass, based on 100% by mass of the styrenic block copolymer (A1). If the styrene content is less than 40% by mass, the stress retention rate during elongation at high temperatures of the elastic member formed using the hot melt composition will decrease. When the styrene content exceeds 65% by mass, the hot melt composition becomes hard and the elastic member cannot exhibit sufficient extensibility.
• the styrene content of the styrenic block copolymer (A1) is preferably 40 to 65% by mass, more preferably 40 to 63% by mass.
• styrene content of a styrenic block copolymer refers to the content ratio (mass %) of styrene blocks in the styrenic block copolymer.
• the method for calculating the styrene content in the styrenic block copolymer in this specification is not particularly limited, and examples thereof include methods using proton nuclear magnetic resonance method or infrared spectroscopy according to JIS K6239. .
• the styrenic block copolymer (A1) may be used singly or in combination of two or more, as long as it has a styrene content of 40 to 65% by mass.
• a styrenic block copolymer (A1) with a high styrene content and a styrenic block copolymer (A1) with a low styrene content are mixed and used. It's okay. That is, when two or more types are used as a mixture, in the hot melt composition of the present invention, the styrene content of each styrenic block copolymer (A1) is within the above range.
• the styrenic block copolymer (A1) is a hydrogenated styrenic block copolymer.
• the styrenic block copolymer is a hydrogenated product of a styrenic block copolymer, and is also referred to as a hydrogenated styrenic block copolymer. More specifically, the hydrogenated styrenic block copolymer is produced by block copolymerizing a vinyl aromatic hydrocarbon and a conjugated diene compound, and forming blocks based on the conjugated diene compound in the obtained block copolymer. It is a fully or partially hydrogenated block copolymer.
• the above-mentioned vinyl aromatic hydrocarbon is an aromatic hydrocarbon compound having a vinyl group.
• vinyl aromatic hydrocarbons include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, ⁇ -methylstyrene, vinylnaphthalene, and vinylanthracene. Among these, styrene is preferred.
• Vinyl aromatic hydrocarbons may be used alone or in combination of two or more.
• the above conjugated diene compound is a diolefin compound having at least one pair of conjugated double bonds.
• the conjugated diene compound includes 1,3-butadiene, 2-methyl-1,3-butadiene (or isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1 , 3-hexadiene, etc.
• 1,3-butadiene and 2-methyl-1,3-butadiene are preferred.
• the conjugated diene compounds may be used alone or in combination of two or more.
• the hydrogenated ratio in the hydrogenated styrenic block copolymer (A1) is indicated as "hydrogenation rate".
• the "hydrogenation rate" of the styrenic block copolymer (A1) is based on all the ethylenically unsaturated double bonds contained in the block based on the conjugated diene compound, and among them, saturated hydrocarbons are hydrogenated. Refers to the percentage of ethylenically unsaturated double bonds converted to bonds.
• the hydrogenation rate can be measured using an infrared spectrophotometer, a nuclear magnetic resonance device, or the like.
• the hydrogenated styrenic block copolymer (A1) partially hydrogenated and fully hydrogenated hydrogenated products can be used. Among these, fully hydrogenated hydrogenated products are preferred. Since the styrenic block copolymer is completely hydrogenated, the heating stability of the hot melt composition is further improved.
• the hydrogenation rate of the styrenic block copolymer (A1) is preferably about 100%.
• the content of the styrenic block copolymer (A1) in the hot melt composition of the present invention is preferably 20 to 50% by mass, more preferably 25 to 40% by mass, based on 100% by mass of the hot melt composition. More preferably 30 to 35% by mass.
• the melt flow rate (MFR) of the styrenic block copolymer (A1) is preferably less than 10 g/10 min, more preferably less than 7 g/10 min.
• the lower limit of the melt flow rate is not particularly limited, and is preferably a value greater than 0, more preferably over 1 g/10 min, and even more preferably over 3 g/10 min.
• melt flow rate is a value measured at 260° C. and a load of 5 kg by a measuring method based on ISO1133.
• thermoplastic resin (A) constituting the hot melt composition of the present invention may contain a thermoplastic resin other than the styrenic block copolymer (A1).
• thermoplastic resins commonly used in hot melt compositions can be used.
• a styrenic block copolymer (A2) other than the styrenic block copolymer (A1) can be used.
• the other styrenic block copolymers (A2) include hydrogenated styrenic block copolymers having a styrene content of less than 40% by mass and more than 65% by mass.
• the hydrogenated styrenic block copolymer having a styrene content of less than 40% by mass and more than 65% by mass, which is used as the other styrenic block copolymer (A2), is not particularly limited, and for example, styrene- Ethylene-butylene-styrene copolymer (SEBS), styrene-butylene-butadiene-styrene copolymer (SBBS), styrene-ethylene-butylene/styrene-styrene copolymer (SEB/S-S), styrene-ethylene- Examples include propylene-styrene copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene copolymer (SEEPS), and styrene-ethylene-butylene-olefin crystal copolymer (SEBC).
• SEBS sty
• styrene-ethylene-butylene-styrene copolymer styrene-ethylene-butylene copolymer, styrene-ethylene-butylene copolymer, etc.
• Styrene-styrene copolymers are preferred.
• the above-mentioned other styrenic block copolymers (A2) may be used alone or in combination of two or more.
• the above styrene-ethylene-butylene-styrene copolymer is a copolymer in which the terminal styrene units form an end block phase and the ethylene-butylene units form a mid-block phase. Furthermore, when using a copolymer in which the mid-block phase is hydrogenated ethylene-butylene units, the polarity difference with the styrene units in the end-block phase becomes more pronounced, and the copolymerization of the non-hydrogenated mid-block phase becomes more pronounced. Compared to coalescence, the styrene units in the end block phase become stronger. As a result, the stretch recovery properties of the hot melt composition can be further improved. Furthermore, when the mid-block phase is hydrogenated, it is possible to provide a hot melt composition with even better heating stability.
• styrene-ethylene-butylene-styrene copolymer Commercially available products can be used as the styrene-ethylene-butylene-styrene copolymer.
• Commercially available products include G1654 manufactured by Clayton Polymer Co., Ltd., and Tuftec H1041 and H1043 manufactured by Asahi Kasei Corporation.
• the styrene content of the other styrenic block copolymer (A2) is preferably less than 40% by mass and more than 65% by mass, with the styrenic block copolymer (A2) being 100% by mass.
• the styrene content may be 35% by mass or less, or 30% by mass or less. Further, the styrene content may be 67% by mass or more and 70% by mass or more.
• the content of the other styrenic block copolymer (A2) in the hot melt composition of the present invention is preferably 0.1 to 10% by mass, and 0.5 to 7% by mass, based on 100% by mass of the hot melt composition. .5% by weight is more preferable, and 1 to 5% by weight is even more preferable. Since the content of the other styrenic block copolymer (A2) is within the above range, the stretchable member formed using the hot melt composition of the present invention has even better stress retention properties when stretched at high temperatures. , and the coating suitability of the hot melt composition is further improved.
• the hot melt composition of the present invention contains a plasticizer (B).
• the plasticizer (B) is preferably liquid at 23°C. Note that in this specification, "liquid” refers to a state exhibiting fluidity.
• the pour point of such a plasticizer (B) is preferably 23°C or lower, more preferably 10°C or lower.
• pour point is a value measured by a measuring method based on JIS K2269.
• the plasticizer (B) is not particularly limited, and includes, for example, paraffinic process oil, naphthenic process oil, aromatic process oil, liquid paraffin oil, and the like.
• paraffinic process oils, naphthenic process oils, and liquid paraffin oils are preferred, and paraffinic process oils and naphthenic process oils are more preferred, from the viewpoint of excellent heating stability.
• paraffin processing oil is more preferable from the viewpoint of further improving the stress maintenance properties of the elastic member formed using the hot melt composition during expansion at high temperatures.
• liquid paraffin oil Commercially available products can be used as the liquid paraffin oil. Commercially available products include P-100 manufactured by MORESCO and Kaydol manufactured by Sonneborn.
• the above plasticizer (B) may be used alone or in a mixture of two or more.
• the content of the plasticizer (B) in the hot melt composition of the present invention is preferably 25 to 75% by mass, more preferably 30 to 70% by mass, and 50 to 65% by mass, based on 100% by mass of the hot melt composition. % is more preferable.
• the upper limit of the content of the plasticizer (B) is within the above range, the stress maintenance property of the stretchable member formed using the hot melt composition during stretching at high temperatures is further improved.
• the lower limit of the content of the plasticizer (B) is within the above range, the melt viscosity of the hot melt composition is further reduced, and the coating suitability of the hot melt composition is further improved.
• the hot melt composition of the present invention preferably contains a hydrocarbon resin (C).
• the hydrocarbon resin (C) is a component that acts as a tackifier or an end block resin.
• the stress retention rate of the hot melt composition of the present invention is further improved while suppressing an increase in melt viscosity.
• the above hydrocarbon resin (C) is a hydrocarbon resin other than the thermoplastic resin (A) and the plasticizer (B).
• the hydrocarbon resin (C) is the styrene block copolymer, polyolefin copolymer, polyacrylic copolymer, polyamide copolymer, or polyester copolymer described in (A1) and (A2) above. , it is preferable that it does not contain a polyurethane copolymer. More specifically, the hydrocarbon resin (C) includes tackifying resins, aromatic hydrocarbon resins, and the like.
• Tackifying resins include natural rosin, modified rosin, glycerol ester of natural rosin, glycerol ester of modified rosin, pentaerythritol ester of natural rosin, pentaerythritol ester of modified rosin, copolymer of natural terpene, three-dimensional polymer of natural terpene, Hydrogenated derivatives of copolymers of natural terpenes, terpene resins, hydrogenated derivatives of phenolic modified terpene resins; petroleum resins such as C5 petroleum resins, C9 petroleum resins, C5C9 petroleum resins, dicyclopentadiene petroleum resins, Partially hydrogenated petroleum resins, fully hydrogenated petroleum resins, etc., which are obtained by adding hydrogen to these petroleum resins, can be mentioned.
• tackifying resin petroleum resins, partially hydrogenated petroleum resins, and fully hydrogenated petroleum resins are preferable in terms of the odor and thermal stability of the hot melt composition. Added petroleum resin is more preferred. These tackifier resins may be used alone or in combination of two or more.
• the aromatic hydrocarbon resin is a resin that acts as an end block resin for the resin component forming the hot melt composition.
• the aromatic hydrocarbon resin is not particularly limited, and for example, vinyl aromatic hydrocarbons can be used.
• a vinyl aromatic hydrocarbon is an aromatic hydrocarbon compound having a vinyl group.
• Specific examples of vinyl aromatic hydrocarbons include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, ⁇ -methylstyrene, vinylnaphthalene, and vinylanthracene. Among these, styrene and ⁇ -methylstyrene are preferred.
• the content of the hydrocarbon resin (C) is preferably 1 to 45% by mass, more preferably 2 to 35% by mass, and even more preferably 5 to 20% by mass, based on 100% of the hot melt composition.
• the hot melt composition of the present invention may contain other additives as long as they do not essentially impede the object of the present invention.
• the other additives include antioxidants, ultraviolet absorbers, photopolymerization initiators, liquid rubbers, and particulate fillers.
• antioxidants 2,6-di-t-butyl-4-methylphenol, n-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate, 2, 2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 2,4-bis(octylthiomethyl)-o-cresol, 2 -t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenylacrylate, 2,4-di-t-amyl-6-[1-(3,5 -di-t-amyl-2-hydroxyphenyl)ethyl]phenylacrylate, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)]acrylate, tetrakis[methylene-3-(3, Hindered phenolic
• the content of the antioxidant in the hot melt composition of the present invention is preferably 0.01 to 2% by mass, more preferably 0.05 to 1.5% by mass, based on 100% by mass of the hot melt composition. , 0.1 to 1% by mass is more preferable.
• the content of the antioxidant is 0.01% by mass or more, the thermal stability of the hot melt composition is further improved.
• the content of the antioxidant is 2% by mass or less, the odor of the hot melt composition is reduced.
• UV absorbers 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-t-butylphenyl)benzotriazole, 2-(2' Benzotriazole UV absorbers such as -hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole; Benzophenone UV absorbers such as 2-hydroxy-4-methoxybenzophenone; Salicylic acid esters Examples include ultraviolet absorbers; cyanoacrylate ultraviolet absorbers; and hindered amine light stabilizers. The ultraviolet absorbers may be used alone or in combination of two or more.
• the content of the ultraviolet absorber in the hot melt composition of the present invention is preferably 0.01 to 2% by mass, more preferably 0.05 to 1.5% by mass, based on 100% by mass of the hot melt composition. , 0.1 to 1% by mass is more preferable.
• the content of the ultraviolet absorber is 0.01% by mass or more, the weather resistance of the hot melt composition is improved.
• the content of the ultraviolet absorber is 2% by mass or less, the odor of the hot melt composition is reduced.
• the photopolymerization initiator examples include ultraviolet polymerization initiators.
• the hot melt composition of the present invention contains a styrenic block copolymer having a reactive polystyrene hard block in the molecule as the styrenic block copolymer (A), it further contains a photopolymerization initiator.
• the reactive polystyrene hard blocks react, molecules are crosslinked, and properties such as dynamic viscoelasticity of the hot melt composition can be adjusted. .
• the irradiation intensity of the ultraviolet rays is preferably about 50 to 1,000 mW/cm 2
• the cumulative light amount is preferably about 1,000 to 15,000 mJ/cm 2 to achieve desired properties. You can adjust it appropriately to make it.
• the photopolymerization initiators may be used alone or in combination of two or more.
• liquid rubber examples include liquid polybutene, liquid polybutadiene, liquid polyisoprene, and hydrogenated resins thereof.
• One type of liquid rubber may be used alone, or two or more types may be used in combination.
• the content of liquid rubber in the hot melt composition of the present invention is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, and even more preferably 3 to 10% by mass, based on 100% by mass of the hot melt composition.
• the content of liquid rubber is 1% by mass or more, the melt viscosity of the hot melt composition is reduced, and the coating suitability is further improved.
• the content of liquid rubber is 20% by mass or less, the hot melt composition does not become too soft, and the elastic recovery properties of the elastic member are further improved.
• the particulate filler is not particularly limited, and examples thereof include calcium carbonate, kaolin, talc, titanium oxide, mica, styrene beads, and the like.
• the fine particle fillers may be used alone or in combination of two or more.
• the hot melt composition of the present invention can be manufactured by a known method.
• a thermoplastic resin (A), a plasticizer (B), and if necessary various additives such as a hydrocarbon resin (C) are charged into a double-arm kneader heated to 150 to 170°C and heated. It is manufactured by melt-kneading.
• the hot melt composition of the present invention is usually solid in the temperature range of 0 to 60°C, particularly at room temperature of 23°C, and exhibits elasticity. Therefore, the elastic member formed using the hot melt composition of the present invention is , can be used for various purposes.
• the uses of the hot melt composition of the present invention are not particularly limited, and include, for example, absorbent articles including sanitary materials, hospital gowns, masks, etc.
• sanitary materials include paper diapers, sanitary napkins, and the like.
• a laminate can be produced by bonding porous substrates using the hot melt composition of the present invention.
• the laminate is suitably used for absorbent articles and the like.
• porous substrate examples include nonwoven fabric, paper, and the like.
• the nonwoven fabric is not particularly limited, and examples include spunbond nonwoven fabric, spunlace nonwoven fabric, needle punched nonwoven fabric, and the like.
• a stretchable laminate with good texture can be created.
• a stretchable nonwoven fabric can also be used as the nonwoven fabric.
• a stretchable laminate can be created by applying the hot melt composition of the present invention without stretching the stretchable nonwoven fabric and bonding the stretchable nonwoven fabrics together.
• the stretchable nonwoven fabric described above stretches a certain amount by pulling it in a certain direction, but it is difficult to return to its original length when the pulling force is removed.
• a porous substrate such as a stretchable nonwoven fabric to form a laminate
• it functions as a stretchable reinforcing material and gives the laminate the ability to return to its original length. be able to.
• the stretchable nonwoven fabric is not particularly limited, and examples thereof include spunlace nonwoven fabric, needle punched nonwoven fabric, and the like.
• the coating method for applying the hot melt composition to the porous substrate is not particularly limited, and examples thereof include slot coating, curtain spray coating, spiral spray coating, film coating, and the like.
• the amount of the hot melt composition applied to the porous substrate is not particularly limited, and is preferably from 1 to 200 g/m 2 , more preferably from 5 to 150 g/m 2 , even more preferably from 10 to 100 g/m 2 .
• the lower limit of the coating amount is within the above range, the stress and expansion/contraction recovery rate of the laminate are further improved.
• the upper limit of the coating amount is within the above range, the feel of the laminate is further improved.
• A1536 (styrene content 42% by mass) ⁇ Hydrogenated styrenic block copolymer (A1-3) Styrene-ethylene-butylene/styrene-styrene copolymer (SEB/S-S) manufactured by Kraton Polymer Co., Ltd.
• A1535 (styrene content 57% by mass)
• SEBS Styrene-ethylene-butylene-styrene
• Tuftec H1043 (styrene content 67% by mass) ⁇ Hydrogenated styrenic block copolymer (A2-3) Styrene-ethylene-butylene-styrene (SEBS) copolymer manufactured by Asahi Kasei Co., Ltd.
• Tuftec H1041 (styrene content 30% by mass) ⁇ Hydrogenated styrenic block copolymer (A2-4) Styrene-ethylene-butylene-styrene (SEBS) manufactured by Kraton Polymer Co., Ltd. G1654 (styrene content 30% by mass)
• Hydrocarbon resin (C) ⁇ Hydrocarbon resin (C1) C5 hydrocarbon resin Eastman Chemical C100L ⁇ Hydrocarbon resin (C2) Styrenic resin Piccolastic A75 manufactured by Eastman Chemical ⁇ Hydrocarbon resin (C3) ⁇ -methylstyrene resin manufactured by Mitsui Chemicals FTR-0120
• Antioxidant ⁇ Phenolic antioxidant Evernox10 manufactured by Japan Specialty Chemicals
• Example and comparative example The above-mentioned raw materials were put into a stirring kneader equipped with a heating device in the amounts shown in Table 1. A hot melt composition was prepared by kneading while heating at 160° C. for 90 minutes.
• the properties of the obtained hot melt composition and the elastic member manufactured using the hot melt composition were measured under the following measurement conditions, and the characteristics were evaluated.
• melt viscosity at 180°C The hot melt composition was heated and melted, and the viscosity of the melted state at 180° C. was measured using a Brookfield RVT viscometer (spindle No. 29) by adjusting the rotational speed within a measurable range.
• the softening point (ring and ball softening point) of the hot melt composition was measured by a measuring method based on JIS K6863-1994.
• test piece (expandable member)
• the hot melt composition was applied at a coating temperature of 160 to 180° C. to the release layer side of the release-treated PET film to a thickness of 50 ⁇ m or 150 ⁇ m.
• the coating width was 100 mm.
• one side was laminated with release paper that had been subjected to release treatment to produce a laminate.
• the obtained laminate was cut into a size of 25 mm in the width direction and 50 mm in the coating direction, or a size of 50 mm in the width direction and 100 mm in the coating direction.
• test piece of the hot melt composition with a width of 25 mm and a length of 50 mm, and a test piece (stretchable member) with a width of 50 mm and a length of 100 mm.
• the longitudinal direction (hot melt composition application direction (MD direction)) and the perpendicular direction (CD direction) are vertically aligned to a tensile tester (manufactured by Shimadzu Corporation, product name: AGS-X) with a jig spacing of 50 mm. Fix both ends of the test piece (width (MD direction) 50 mm, length (CD direction) 100 mm, thickness 50 ⁇ m) in the coating direction with a jig so that the test piece is in the same position, and the test piece is broken in the vertical direction at a tensile speed of 500 mm/min. I pulled it until it was.
• MD direction hot melt composition application direction
• CD direction perpendicular direction
• the longitudinal direction (hot melt composition application direction (MD direction)) and the perpendicular direction (CD direction) are vertically aligned to a tensile tester (manufactured by Shimadzu Corporation, product name: AGS-X) with a jig spacing of 50 mm. Fix the test piece (width (MD direction) 50 mm, length (CD direction) 100 mm, thickness 50 ⁇ m) with a jig so that it is in the same position, and move it up and down at a tensile speed of 500 mm/min until the strain displacement of the test piece becomes 300%. pulled in the direction. Then, it was returned to the initial position at a speed of 500 mm/min.
• Stress retention rate stress retention during elongation at high temperature
• the stress retention rate was measured after holding the film in a 2-fold stretched state for 1 hour at a temperature of 40°C. Specifically, in a 40°C environment, the test was carried out in the longitudinal direction (in the application direction of the hot melt composition (MD direction)) using a tensile tester (manufactured by Shimadzu Corporation, product name: EZ-LX) with a jig distance of 25 mm.
• test piece width (MD direction) 25 mm, length (CD direction) 50 mm, thickness 150 ⁇ m
• the hot melt composition was put into a melting tank heated to 180°C, and discharged from a slot nozzle heated to 180°C, onto a release-treated PET film at a coating amount of 50 g/m 2 and a coating width of 100 mm. Contact coated. The coating status was visually observed and evaluated according to the following evaluation criteria.
• C Coating unevenness is observed, but it is not a problem in actual use.
• D Significant coating unevenness is observed, or a predetermined amount of hot melt composition is not discharged.

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• 2023
  • 2023-04-07 WO PCT/JP2023/014429 patent/WO2023195539A1/ja not_active Ceased
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