JP4848184B2 - Hot melt adhesives and disposable products - Google Patents

Description

  The present invention relates to a hot melt adhesive, and more particularly to a hot melt adhesive used in the field of disposable products represented by disposable diapers and napkins.

  Synthetic rubber hot melt mainly composed of a thermoplastic block copolymer as a hot melt adhesive used for disposable products such as diapers and napkins and applied to its base materials such as nonwoven fabrics, tissues and polyethylene films An olefin-based hot melt adhesive represented by an adhesive and an ethylene-propylene-butene copolymer can be mainly exemplified. However, in recent years, due to problems such as low coating suitability and low cohesive force, olefin-based The use of hot melt adhesives has decreased, and synthetic rubber hot melt adhesives having good coating suitability are widely used.

  Many diapers, napkins, and the like have a structure in which an absorbent body composed of pulp and an absorbent polymer is wrapped in a tissue and the outer side thereof is covered with a nonwoven fabric, a polyethylene film, and the like. Generally, synthetic rubber-based hot melt adhesives have low affinity for natural materials such as cellulosic materials (tissue, pulp, etc.) and cotton materials, and when these materials get wet with body fluids such as urine, that is, wet. In the state, it has the property that the adhesive strength is significantly reduced. In particular, when a synthetic rubber-based hot melt adhesive is used for adhesion between tissues or between a tissue and a non-woven fabric, the adhesive between the tissue and the tissue or between the tissue and the non-woven fabric peels off in a wet state. It has been pointed out that the fluid absorption is reduced.

  As a means for preventing a decrease in the adhesive strength in a wet state, a method using an olefinic hot melt adhesive can be exemplified, but the olefinic hot melt adhesive is used when it is used in a spray coating machine represented by a spiral spray or the like. The coating suitability may not be sufficient.

  Patent Document 1 discloses a hot melt adhesive containing a thermoplastic block copolymer modified with an acid (specifically, a carboxyl group), which is disclosed as preferable for a disposable sanitary product. ing. Furthermore, it is also disclosed that by using this hot melt adhesive, it is possible to improve wet adhesion while maintaining good spray coating suitability. However, in general, a hot melt adhesive containing a thermoplastic copolymer block modified with an acid can cause a decrease in adhesive strength and a decrease in cold resistance.

  An adhesive composition comprising acid-modified SEBS and SIS is disclosed in Patent Document 2 in order to improve the decrease in adhesive strength and cold resistance. However, when the amount of SIS added is large, the viscosity of the adhesive composition becomes high, so that the coating suitability can be lowered, and further the wet strength of the cured adhesive product can be lowered. In addition, when an adhesive composition containing such acid-modified SEBS is used as a hot melt adhesive by heating, the problem that the acidic component modifying SEBS promotes thermal degradation of SIS arises. In addition, since unreacted monomers can remain in the acid-modified SEBS, many acid-modified SEBS have odor. Accordingly, adhesive compositions containing acid-modified SEBS can also have odors, and therefore, adhesive compositions containing acid-modified SEBS are not particularly suitable for disposable product applications that should be sensitively considered to have odors. .

  By the way, in general, modification of a thermoplastic block copolymer using an acid is carried out by graft polymerization, for example, by passing the copolymer together with an acid and a catalyst through an extruder under high temperature and high shear. When block copolymers such as styrene-isoprene block copolymer (SIS) and styrene-butadiene block copolymer (SBS), which do not necessarily have excellent thermal stability, are modified with an acid, loads such as temperature and shear are applied during the graft polymerization process. Therefore, the block copolymer is likely to be decomposed. For this reason, many block copolymers obtained by acid-modifying hydrogenated styrene-butadiene block copolymers (SEBS: styrene-ethylene-butylene-styrene copolymers) are commercially available. However, the hot melt adhesive mainly composed of SEBS has a high glass transition temperature (Tg) of the mid block and lacks flexibility as compared with unhydrogenated block copolymers such as SIS and SBS. Therefore, the balance between cohesive force and tackiness of the obtained hot melt adhesive is deteriorated, and the adhesiveness tends to be inferior. Furthermore, the block copolymer modified with an acid can be exemplified as one of the problems that the cost is high due to problems of raw materials and production processes.

JP 2005-104996 A JP 2000-119620 A

  The present invention relates to a synthetic rubber-based hot-melt adhesive, and improves adhesiveness in a wet state (hereinafter also referred to as “wet adhesiveness”) to hydrophilic substrates such as cellulose-based substrates and cotton-based substrates. More preferably, the object is to provide a hot melt adhesive improved in at least one selected from low-temperature adhesiveness, viscosity, adhesiveness, odor and economy. Furthermore, there is provided a method for producing a synthetic rubber-based hot melt adhesive having improved wet adhesion, and more preferably at least one selected from low temperature adhesion, viscosity, adhesion, odor, and economy. For the purpose. Further, the wet adhesiveness of such a synthetic rubber-based hot melt adhesive is improved, and more preferably, an improvement for improving at least one selected from low-temperature adhesiveness, viscosity, adhesiveness, odor, and economy. The object is to provide an agent (or additive).

  As a result of intensive studies, the present inventors have found that when a wax component having a polar group introduced is added to a synthetic rubber hot melt adhesive, the wet adhesiveness is higher than that of a conventional synthetic rubber hot melt adhesive. The present invention has been found to be improved, and the present invention has been completed.

  That is, the present invention is modified with (A) a thermoplastic block copolymer which is a copolymer of a vinyl aromatic hydrocarbon and a conjugated diene compound, and (B) a carboxylic acid and / or a carboxylic anhydride. A hot melt adhesive comprising a wax is provided.

  In one embodiment of the invention, (A) the thermoplastic block copolymer comprises a styrene-isoprene block copolymer (SIS), a styrene-butadiene block copolymer (SBS), a hydrogenated styrene-isoprene block copolymer (SEPS) and A hot melt adhesive is provided that is at least one selected from hydrogenated styrene-butadiene block copolymers (SEBS).

  In another aspect of the present invention, there is provided a hot melt adhesive wherein (B) the wax modified with carboxylic acid and / or carboxylic anhydride is a polyolefin wax modified with maleic acid and / or maleic anhydride. .

  In a preferred embodiment of the present invention, the composition further comprises (C) a tackifier resin and (D) a plasticizer, and the total of (A) a thermoplastic block copolymer, (C) a tackifier resin and (D) a plasticizer. As 100 parts by weight, (A) 10 to 35 parts by weight of a thermoplastic block copolymer, (B) 0.3 to 5.0 parts by weight of a wax modified with a carboxylic acid and / or carboxylic anhydride, (C) A hot melt adhesive comprising 45 to 80 parts by weight of a tackifier resin and (D) 3 to 25 parts by weight of a plasticizer is provided.

  Furthermore, the present invention provides a disposable product obtained by applying the hot melt adhesive according to the present invention.

  The present invention also relates to (B) a thermoplastic block which is a copolymer of (A) a vinyl aromatic hydrocarbon and a conjugated diene compound, using a wax modified with carboxylic acid and / or carboxylic anhydride. A method of making a hot melt adhesive having improved wet adhesion comprising a copolymer is provided.

  Furthermore, the present invention relates to (B) a thermoplastic resin which is a copolymer of a vinyl aromatic hydrocarbon and a conjugated diene compound, which contains a wax modified with a carboxylic acid and / or a carboxylic acid anhydride. A wet adhesion improver for a hot melt adhesive comprising a block copolymer is provided.

  The hot melt adhesive of the present invention comprises (A) a thermoplastic block copolymer that is a copolymer of a vinyl aromatic hydrocarbon and a conjugated diene compound, and (B) a carboxylic acid and / or a carboxylic anhydride. Since it contains a modified wax, wet adhesion is improved, more preferably at least one selected from low-temperature adhesion, viscosity, adhesion, odor, and economy.

  The hot melt adhesive (A) thermoplastic block copolymer of the present invention comprises a styrene-isoprene block copolymer (SIS), a styrene-butadiene block copolymer (SBS), a hydrogenated styrene-isoprene block copolymer (SEPS) and In the case of at least one selected from hydrogenated styrene-butadiene block copolymer (SEBS), the wet adhesion can be further improved.

  When the wax modified with (B) carboxylic acid and / or carboxylic anhydride of the hot melt adhesive of the present invention is a polyolefin wax modified with maleic acid and / or maleic anhydride, the wet adhesiveness is further improved. Can be improved further.

The hot melt adhesive of the present invention is
And further comprising (C) a tackifying resin and (D) a plasticizer,
(A) 10 to 35 parts by weight of a thermoplastic block copolymer, (B) 0.3 to 5.0 parts by weight of a wax modified with a carboxylic acid and / or carboxylic anhydride, and (C) a tackifying resin 45 to 45 parts by weight. In the case of comprising 80 parts by weight and (D) 3 to 25 parts by weight of a plasticizer, the wet adhesion and the dry adhesion can be further improved.

  Accordingly, when the hot melt adhesive of the present invention is used for absorbent articles such as disposable diapers and napkins, the wet characteristics of the hot melt adhesive are improved, so that the tissue and nonwoven fabric of the article member can be compared with body fluids such as urine and blood. Even if it gets wet, it becomes difficult for members to separate. That is, the wet characteristics of the resulting product are also improved. Furthermore, since at least one selected from the low-temperature adhesiveness, viscosity, adhesiveness, odor, and economy of the hot melt adhesive of the present invention can be improved, the adhesive strength, viscosity, and adhesiveness of the resulting product at low temperatures. At least one selected from odor, manufacturing cost can also be improved.

  In addition, the method for producing a hot melt adhesive having improved wet characteristics according to the present invention uses (B) a wax modified with a carboxylic acid and / or a carboxylic anhydride, so that the wet adhesiveness can be improved. More preferably, at least one selected from low-temperature adhesiveness, viscosity, adhesiveness, odor, and economy is improved.

  Furthermore, the wet property improving agent of the hot melt adhesive of the present invention contains (B) a wax modified with a carboxylic acid and / or carboxylic anhydride, so that the wet adhesive property of the hot melt adhesive is improved. More preferably, at least one selected from low-temperature adhesiveness, viscosity, adhesiveness, odor, and economy can be improved.

  In the present specification, the carboxylic acid and / or carboxylic anhydride means at least one selected from carboxylic acid and carboxylic anhydride.

  In the present invention, “(A) thermoplastic block copolymer” is a copolymer obtained by block copolymerization of a vinyl aromatic hydrocarbon and a conjugated diene compound, and is usually a vinyl aromatic hydrocarbon block. If it has a conjugated diene compound block and can obtain the hot melt adhesive which is the object of the present invention, it is not particularly limited.

  Here, the “vinyl aromatic hydrocarbon” means an aromatic hydrocarbon compound having a vinyl group. Specifically, for example, styrene, o-methylstyrene, p-methylstyrene, p-tert- Examples include butyl styrene, 1,3-dimethyl styrene, α-methyl styrene, vinyl naphthalene, and vinyl anthracene. Styrene is particularly preferable. These vinyl aromatic hydrocarbons can be used alone or in combination.

  The “conjugated diene compound” means a diolefin compound having at least a pair of conjugated double bonds. Specific examples of the “conjugated diene compound” include 1,3-butadiene, 2-methyl-1,3-butadiene (or isoprene), 2,3-dimethyl-1,3-butadiene, and 1,3- Examples thereof include pentadiene and 1,3-hexadiene. 1,3-butadiene and 2-methyl-1,3-butadiene are particularly preferred. These conjugated diene compounds can be used alone or in combination.

  The thermoplastic block copolymer (A) according to the present invention may be an unhydrogenated product or a hydrogenated product.

  Specific examples of “(A) an unhydrogenated product of a thermoplastic block copolymer” include those in which a block based on a conjugated diene compound is not hydrogenated. Further, “(A) hydrogenated product of thermoplastic block copolymer” specifically includes a block copolymer in which all or a part of the block based on the conjugated diene compound is hydrogenated.

  The ratio of “(A) the hydrogenated product of the thermoplastic block copolymer” which is hydrogenated can be represented by “hydrogenation rate”. The “hydrogenation ratio” of “(A) hydrogenated thermoplastic block copolymer” is based on the total aliphatic double bonds contained in the block based on the conjugated diene compound, in which hydrogenation is performed. The ratio of double bonds converted to saturated hydrocarbon bonds. This “hydrogenation rate” can be measured by an infrared spectrophotometer, a nuclear magnetic resonance apparatus, or the like.

Specific examples of “(A) unhydrogenated thermoplastic block copolymer” include, for example, styrene-isoprene block copolymer (also referred to as “SIS”) and styrene-butadiene block copolymer (also referred to as “SBS”). It can be illustrated. Specific examples of “(A) hydrogenated thermoplastic block copolymer” include, for example, hydrogenated styrene-isoprene block copolymer (also referred to as “SEPS”) and hydrogenated styrene-butadiene block copolymer ( (Also referred to as “SEBS”).
(A) The thermoplastic block copolymer can be used alone or in combination.

  (A) A commercial item can be used as a thermoplastic block copolymer. For example, Asapurene T439 (trade name), Asaprene T436 (trade name), Asaprene T438 (trade name), Asaprene N505 (trade name) and Taffeprene T125 (trade name) manufactured by Asahi Kasei Kogyo Co., Ltd .; TR2003 (trade name), TR 2500 (trade name) and TR 2600 (trade name); Stereon 857 (trade name) and Stereon 841A (trade name) manufactured by Firestone; Clayton D1118 (trade name) manufactured by Kraton Polymer Examples thereof include Sol T166 (trade name) manufactured by Enichem Co., Ltd .; QUINT 3433N (trade name) and QUINT 3421 (trade name) manufactured by Nippon Zeon Co., Ltd. These commercially available products of the thermoplastic block copolymer (A) can be used alone or in combination.

  The hot melt adhesive according to the present invention contains (B) a wax modified with carboxylic acid and / or carboxylic anhydride. When a hydrophilic natural sheet such as tissue or cotton is bonded with the hot melt adhesive of the present invention, (B) the wax improves the wet adhesion extremely effectively, and the tissue or non-woven fabric wetted by body fluids is peeled off. Can be prevented.

  The (B) wax is not particularly limited as long as the hot melt adhesive targeted by the present invention can be obtained as long as it is modified with carboxylic acid and / or carboxylic anhydride. As such (B) wax, a wax obtained by graft polymerization of carboxylic acid and / or carboxylic anhydride to a base wax, and carboxylic acid and / or carboxylic anhydride when synthesizing the wax by polymerization are used. Examples thereof include waxes obtained by copolymerization. Therefore, the carboxylic acid and / or carboxylic anhydride may be introduced and modified as a result using various reactions.

The above-mentioned “base wax” is a wax generally used for hot melt adhesives, and is not particularly limited as long as the hot melt adhesive intended by the present invention can be obtained. Absent. Specifically, synthetic wax systems such as Fischer-Tropsch wax and polyolefin wax (polyethylene wax, polypropylene wax);
Petroleum waxes such as paraffin wax and microcrystalline wax;
Natural waxes such as castor wax;
Etc. can be illustrated.

  The carboxylic acid and / or carboxylic anhydride used for modifying the base wax is not particularly limited as long as the hot melt adhesive intended by the present invention can be obtained. Specific examples include maleic acid, maleic anhydride, fumaric acid, succinic acid, succinic anhydride, phthalic acid, phthalic anhydride, glutaric acid, glutaric anhydride, itaconic acid, acrylic acid and methacrylic acid. These carboxylic acids and / or carboxylic anhydrides may be used alone or in combination. In the present invention, maleic acid and maleic anhydride are particularly preferred.

Note that various carboxylic acid derivatives may be used as long as polar groups can be introduced as a substance for modifying the base wax. Here, as the “carboxylic acid derivative”, the following can be exemplified:
Carboxylates such as ethyl acetate and vinyl acetate;
Acid halides such as benzoyl bromide;
Amides such as benzamide, N-methylacetamide, N, N-dimethylformamide;
Imides such as succinimide;
Acyl azides such as acetyl azide;
Hydrazides such as propanoyl hydrazide;
Hydroxamic acids such as chloroacetylhydroxamic acid;
lactones such as γ-butyrolactone;
Lactams such as δ-caprolactam.

  In the present invention, the melting point of the (B) wax is preferably 40 to 180 ° C, and particularly preferably 60 to 150 ° C. The melting point can be measured by a method according to ASTM D127. Moreover, it is preferable that the acid value of (B) wax is 5-200 mgKOH / g, and it is especially preferable that it is 30-160 mgKOH / g. The acid value can be measured by a method based on ASTM D1308 or BWM 3.01A.

  The wax modified with (B) carboxylic acid and / or carboxylic anhydride of the present invention is preferably a polyolefin wax modified with maleic acid and / or maleic anhydride, and further modified with maleic anhydride. Polypropylene wax is particularly preferred.

  (B) A commercially available product can be used as the wax modified with carboxylic acid and / or carboxylic anhydride. For example, Licosene PP MA6252 (trade name) manufactured by Clariant and Ceramer 1608 (trade name) manufactured by Toyo Petrolite may be exemplified.

The hot melt adhesive of the present invention may further contain (C) a tackifying resin.
(C) The tackifier resin is not particularly limited as long as it is a resin that is usually used for a hot melt adhesive and can obtain the hot melt adhesive targeted by the present invention.

  Examples of such (C) tackifying resins include 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, water Pentaerythritol ester of rosin, natural terpene copolymer, three-dimensional polymer of natural terpene, hydrogenated derivative of hydrogenated terpene copolymer, polyterpene resin, hydrogenated derivative of phenolic modified terpene resin, aliphatic petroleum hydrocarbon resin, fat Examples of hydrogenated derivatives of aromatic petroleum hydrocarbon resins, aromatic petroleum hydrocarbon resins, hydrogenated derivatives of aromatic petroleum hydrocarbon resins, cycloaliphatic petroleum hydrocarbon resins, hydrogenated derivatives of cycloaliphatic petroleum hydrocarbon resins be able to. These tackifying resins can be used alone or in combination. The tackifying resin may be a liquid type tackifying resin as long as the color tone is colorless to light yellow and has substantially no odor and good thermal stability. Considering these characteristics comprehensively, a hydrogenated derivative such as a resin is preferable as the tackifier resin.

  (C) As a tackifier resin, a commercial item can be used. Examples of such commercially available products include ECR5600 (trade name) manufactured by Tonex, Marcclear H (trade name) manufactured by Maruzen Petrochemical, Clearon K100 (trade name) manufactured by Yasuhara Chemical, and Archon manufactured by Arakawa Chemical. M100 (trade name), Imabe S100 (trade name) manufactured by Idemitsu Petrochemical Co., Ltd., Clearon K4090 (trade name) and Clearon K4100 manufactured by Yasuhara Chemical Co., ECR231C (trade name) manufactured by Tonex, and Eastman Chemical Co., Ltd. Rigalite R7100 (trade name) can be exemplified. These commercially available tackifying resins can be used alone or in combination.

  Further, the hot melt adhesive of the present invention can contain (D) a plasticizer. (D) The plasticizer is blended for the purpose of lowering the melt viscosity of the hot melt adhesive, imparting flexibility, and improving wetness to the adherend, and is compatible with the block copolymer. There is no particular limitation as long as a melt adhesive can be obtained. Examples of the (D) plasticizer include paraffinic oil, naphthenic oil, and aromatic oil. Colorless and odorless paraffinic oil is particularly preferred.

  (D) A commercial item can be used as a plasticizer. For example, White Oil Broom 350 (trade name) manufactured by Kukdong Oil & Chem, Diana Fresia S32 (trade name), Diana Process Oil PW-90 (trade name), DN Oil KP-68 (trade name), BP manufactured by Idemitsu Kosan Co., Ltd. Examples include Energyr M1930 (trade name) manufactured by Chemicals, Kaydol (trade name) manufactured by Crompton, and Primol 352 (trade name) manufactured by Esso. These (D) plasticizers can be used alone or in combination.

  The hot melt adhesive according to the present invention may further contain various additives as necessary. Examples of such various additives include stabilizers and fine particle fillers.

"Stabilizers" are formulated to improve the stability of hot melt adhesives by preventing the molecular weight reduction, gelation, coloring, odor generation, etc. caused by the heat of hot melt adhesives. As long as the hot melt adhesive intended by the present invention can be obtained, there is no particular limitation. Examples of the “stabilizer” include an antioxidant and an ultraviolet absorber.
“Ultraviolet absorbers” are used to improve the light resistance of hot melt adhesives. “Antioxidants” are used to prevent oxidative degradation of hot melt adhesives. Antioxidants and ultraviolet absorbers are generally used for disposable products, and can be used as long as they can obtain a target disposable product to be described later, and are particularly limited. is not.
Examples of antioxidants include phenolic antioxidants, sulfur antioxidants, and phosphorus antioxidants. Examples of ultraviolet absorbers include benzotriazole ultraviolet absorbers and benzophenone ultraviolet absorbers. Furthermore, a lactone stabilizer can also be added. These can be used alone or in combination.

  A commercial item can be used as a stabilizer. For example, Sumilizer GM (trade name), Sumilizer TPD (trade name) and Sumilizer TPS (trade name) manufactured by Sumitomo Chemical Co., Ltd., Irganox 1010 (trade name), Irganox HP2225FF (trade name) manufactured by Ciba Specialty Chemicals Product name), Irgaphos 168 (product name), Irganox 1520 (product name), and JF77 (product name) manufactured by Johoku Chemical Co., Ltd. can be exemplified. These stabilizers can be used alone or in combination.

  The hot melt adhesive of the present invention can further contain a fine particle filler. The fine particle filler is not particularly limited as long as it is a commonly used one, and the hot melt adhesive targeted by the present invention can be obtained. Examples of the “fine particle filler” include mica, calcium carbonate, kaolin, talc, titanium oxide, diatomaceous earth, urea resin, styrene beads, calcined clay, starch and the like. These shapes are preferably spherical, and the dimensions (diameter in the case of a spherical shape) are not particularly limited.

  The hot melt adhesive of the present invention further comprises (C) a tackifier resin and (D) a plasticizer, and comprises (A) a thermoplastic block copolymer, (C) a tackifier resin, and (D) a plasticizer. The total is 100 parts by weight, (A) 10 to 35 parts by weight of the thermoplastic block copolymer, and (B) 0.3 to 5.0 parts by weight of the wax modified with carboxylic acid and / or carboxylic anhydride. (C) It is preferable to comprise 45 to 80 parts by weight of a tackifier resin and (D) 3.0 to 25 parts by weight of a plasticizer.

  (A) The blending ratio of the thermoplastic block copolymer is preferably 10 to 35 parts by weight. If the amount is less than 10 parts by weight, the cohesive force of the hot melt adhesive is reduced, and the reduction of the adhesive force, the change in the adhesive force with time, and the bleeding of the hot melt adhesive can be problematic. If it exceeds 35 parts by weight, the viscosity of the hot melt adhesive will increase, and the applicability will decrease.

  (B) The content of the wax modified with carboxylic acid and / or carboxylic anhydride is preferably 0.3 to 5.0 parts by weight, more preferably 0.5 to 3.0 parts by weight. preferable. If it is less than 0.3 parts by weight, the effect of improving the wet strength is small, and if it exceeds 5 parts by weight, the tackiness of the hot melt is lowered, and the adhesive force during drying can be lowered.

  (C) As for the compounding ratio of tackifying resin, 45-80 weight part is preferable, and it is more preferable that it is 50-75 weight part. If it is less than 45 parts by weight, the adhesive strength and the adhesiveness are lowered, and if it exceeds 80 parts by weight, the hot melt adhesive becomes brittle and the low-temperature adhesiveness can be lowered.

  (D) The blending ratio of the plasticizer is preferably 3.0 to 25 parts by weight, and more preferably 5.0 to 20 parts by weight. If it is less than 3 parts by weight, it can lead to a decrease in flexibility and tack force of the hot melt, and if it exceeds 25 parts by weight, the adhesive properties can be deteriorated due to a decrease in the cohesive force of the hot melt.

  The hot melt adhesive of the present invention contains the components (A) and (B), optionally (C) and / or (D), and various additives as required, and is heated to melt. It can be manufactured by mixing. Furthermore, when it contains (C) and (D), it is preferable to mix | blend (A), (B), (C), and (D) component in the said predetermined ratio, and to manufacture similarly. Specifically, it can be produced by putting the above components into a melt-mixing kettle equipped with a stirrer and mixing them by heating.

  The hot melt adhesive according to the present invention is widely used for paper processing, bookbinding, disposable products, etc., but is particularly effective for disposable products because of its excellent adhesion in a wet state. The “disposable product” is not particularly limited as long as it is a so-called sanitary material. Specifically, paper diapers, sanitary napkins, pet sheets, hospital gowns, surgical lab coats and the like can be exemplified.

  In another aspect of the present invention, a disposable product obtained by applying the above hot melt adhesive is provided. The disposable product can be constituted by applying the hot melt adhesive according to the present invention to at least one member selected from the group consisting of woven fabric, non-woven fabric, rubber, resin, paper, and polyolefin film. The polyolefin film is preferably a polyethylene film for reasons such as durability and cost.

  In a disposable product production line, a hot melt adhesive is generally applied to various members of a disposable product (for example, tissue, cotton, nonwoven fabric, polyolefin film, etc.). At the time of application, the hot melt adhesive may be ejected from various ejectors.

  The method for applying the hot melt adhesive is not particularly limited as long as the intended disposable product can be obtained. Such a coating method is roughly classified into contact coating and non-contact coating. “Contact application” refers to an application method in which an ejector is brought into contact with a member or a film when hot melt adhesive is applied. “Non-contact application” refers to an ejector that is applied when hot melt adhesive is applied. The coating method which does not contact a member or a film. Examples of the contact coating method include slot coater coating and roll coater coating. Non-contact coating methods include, for example, spiral coating that can be applied in a spiral manner, omega coating that can be applied in a wavy manner, and control seam coating. Examples thereof include slot spray coating and curtain spray coating that can be applied in a planar shape, and dot coating that can be applied in a spot shape.

The present invention also relates to (B) a thermoplastic block which is a copolymer of (A) a vinyl aromatic hydrocarbon and a conjugated diene compound, using a wax modified with carboxylic acid and / or carboxylic anhydride. A method of making a hot melt adhesive having improved wet adhesion comprising a copolymer is provided.
Here, “(B) wax modified with carboxylic acid and / or carboxylic anhydride”, “(A) thermoplastic block copolymer which is a copolymer of a vinyl aromatic hydrocarbon and a conjugated diene compound” "Hot melt adhesive" and the like are as described above. The hot melt adhesive may optionally contain “(C) tackifying resin” and / or “(D) plasticizer”, and the content thereof is preferably as described above. Optionally, other additives may be included.

Furthermore, the present invention relates to (B) a thermoplastic resin which is a copolymer of a vinyl aromatic hydrocarbon and a conjugated diene compound, which contains a wax modified with a carboxylic acid and / or a carboxylic acid anhydride. A wet adhesion improver for a hot melt adhesive comprising a block copolymer is provided.
Also in such an improving agent, “(B) wax modified with carboxylic acid and / or carboxylic anhydride”, “(A) thermoplastic block which is a copolymer of vinyl aromatic hydrocarbon and conjugated diene compound” The “copolymer” and the “hot melt adhesive” are as described above. The hot melt adhesive may optionally contain “(C) tackifying resin” and / or “(D) plasticizer”, and the content thereof is preferably as described above. Optionally, other additives may be included.

Hereinafter, for the purpose of explaining the present invention in more detail and more specifically, the present invention will be described using examples. These examples are for explaining the present invention and do not limit the present invention.
(1) The component for mix | blending a hot-melt-adhesive is shown below.
(A) Thermoplastic block copolymer-Styrene-butadiene-styrene copolymer (SBS)
(A1) Product name “Sol T166” manufactured by Enichem
(A2) Product name “Asaprene T438” manufactured by Asahi Kasei Corporation
・ Styrene-isoprene-styrene block copolymer (SIS)
(A3) Product name “Quintac 3433N” manufactured by Nippon Zeon
(A4) Product name “Quintac 3421” manufactured by Nippon Zeon
・ Maleic acid modified styrene-ethylene-butylene-styrene block copolymer (A'5) Product name "Tuftec M1913" manufactured by Asahi Kasei Corporation

(B) Wax • Maleic anhydride modified polypropylene wax (B1) Product name “Licosene PP MA6252” manufactured by Clariant
Acid value: 40mgKOH / g (according to ASTM D1306) Melting point: 140 ° C (according to ASTM D127)
-Maleic acid-modified polyethylene wax (B2) Product name "Ceramer 1608" manufactured by Toyo Petrolite Co., Ltd.
Acid value: 154mgKOH / g (conforming to BMW 3.01A) Melting point: 77 ° C (conforming to ASTM D127)
・ Polypropylene wax (B'3) Product name "Licosene PP 1602" manufactured by Clariant
Melting point: 90 ° C (according to ASTM D127)

(C) Tackifying resin ・ Hydrogenated terpene resin (C1) Product name “Clearon K4100” manufactured by Yasuhara Chemical Co., Ltd.
・ Hydrogenated CC9 petroleum resin (C2) Product name “Arcon M100” manufactured by Arakawa Chemical Co., Ltd.

(D) Plasticizer-Paraffin oil (D1) Product name White Oil Broom350 manufactured by Kukdon Oil & Chem
(D2) Idemitsu Oil Co., Ltd. Product name Diana Fresia S32
(D3) Idemitsu Oil Co., Ltd. Product name Diana Process Oil PW90

Antioxidant ・ Phenolic primary antioxidant (E1) Product name “Sumilyzer GM” manufactured by Sumitomo Chemical Co., Ltd.
(E2) Product name “Irganox 1010” manufactured by Ciba Specialty Chemicals
・ Sulfur-based secondary antioxidant (E3) Product name “Sumilyzer TPD” manufactured by Sumitomo Chemical Co., Ltd.

These components were blended in the blending ratios shown in Tables 1 and 2, and melt mixed using a universal stirrer at about 150 ° C. for about 3 hours. Examples 1 to 9 and Comparative Examples 1 to 5 hot melt adhesives Adjusted.

(2) For each of the above hot melt adhesives, the melt viscosity, polyethylene film low temperature peel strength, wet vs. cotton peel strength, loop tack and odor were examined using the following methods. The results are shown in Tables 1 and 2.

Melt Viscosity Melt viscosity was measured by melting a hot melt adhesive by heating, and measuring the viscosity in a molten state at 140 ° C. and 160 ° C. using a Brookfield RVT viscometer (spindle No. 27).

Low temperature peel strength (for polyethylene film)
A hot melt adhesive was applied to a 50 μm thick PET film so as to have a thickness of 50 μm. This was molded into a width of 2.5 cm to obtain a test specimen. The polyethylene film was bonded using a 2 kg roller at a rate of 300 mm / min in an atmosphere of 20 ° C., and then cured at room temperature for 24 hours. Thereafter, the strength when peeled at a rate of 300 mm / min in an atmosphere of 10 ° C. was measured. For each hot melt adhesive, three samples were measured and the average value obtained showed the low temperature peel strength. Moreover, the peeling state at low temperature was observed visually. The peeled state is indicated by the following terms.
Cohesive failure (also simply referred to as “aggregation”): hot melt adhesive is adhered to both sides of the substrate.
Interfacial fracture (simply referred to as “interface”)... The hot melt adhesive is adhered to only one substrate.
Zipping: There is unevenness in the peeling speed of the sample, and the peeling strength fluctuates little by little.

Peel strength when wet (on cotton)
A hot melt adhesive was applied to a PET film having a thickness of 50 μm so as to have a thickness of 50 μm. This was molded into a width of 2.5 cm to obtain a test specimen. The sample was bonded to a cotton cloth for JIS dyeing fastness test (Kanakin No. 3) with a 2 kg roller at a rate of 300 mm / min in an atmosphere at 20 ° C. and cured at room temperature for 24 hours. The sample was immersed in tap water adjusted to 20 ° C. in advance for 5 to 6 seconds, lightly wiped off with a tissue, and allowed to stand for about 1 minute. Thereafter, the peel strength was measured at a tensile speed of 300 mm / min using a universal tensile tester. Three samples were measured for each hot melt adhesive, and the average value obtained showed the peel strength against cotton when wet.
◎ means very good wet peel strength, ○ means good wet peel strength, △ means improved wet peel strength compared to conventional products, × means conventional product level Mean wet peel strength.

Loop tack A hot melt adhesive was applied to a 50 μm thick PET film having a thickness of 50 μm. This was molded into a size of 2.5 cm × 10 cm to obtain a test specimen. This test body was wound in a loop shape so that the pressure-sensitive adhesive surface (adhesive-coated surface) was on the outside, and was brought into contact with the PE plate at 20 ° C. at a speed of 300 mm / min. Then, the peak value of the peeling strength when the test body was peeled off from the PE plate at a speed of 300 mm / min was measured.

Odor 35 g of hot melt adhesive was placed in a 70 mL glass bottle, melted, and returned to room temperature. The polymer lid was removed, and the odor of the hot melt adhesive was judged by sensitivity evaluation. ○ means that the odor is hardly felt, △ means that the odor is slightly felt, and x means that It means that the smell is clearly felt.

Overall evaluation ◎ means that it is extremely excellent as a hot melt adhesive for disposable products (or for fixing absorbent bodies) for all items, and ○ is a hot melt adhesive for disposable products for all items. △ means superior to the conventional product and means that it can be used as a hot melt adhesive for disposable products, and × means wet adhesiveness compared to the conventional product. Although improvement is recognized, it means that other items are not improved, and xx means that it is equal to or less than that of the conventional product.

  The hot melt adhesives shown in Examples 1 to 9 in Table 1 showed good adhesive strength particularly with respect to the peel strength when wet (on cotton). Furthermore, melt viscosity, tack force, low-temperature polyethylene film adhesion and low odor were also good, and their balance was also excellent.

  On the other hand, in Comparative Examples 1 to 5 shown in Table 2, the wet peel strength (for cotton) is low. Comparative Example 5 corresponds to the invention described in Patent Document 2, but a slight improvement is seen in the wet peel strength (against cotton), but the degree of improvement is insufficient. Low temperature adhesion (to polyethylene) is also a problem, but this is thought to be related to low tackiness. Also, the odor of the hot melt adhesive is slightly felt.

  The hot melt adhesive of the present invention is considered to have improved wet adhesion by including (B) a wax modified with carboxylic acid and / or carboxylic anhydride. In general, natural products such as cellulose and cotton have a high polarity on their surfaces, so their affinity with synthetic rubber hot melt adhesives with relatively low polarity is not sufficient. Since the hot melt adhesive of the present invention contains (B) a wax modified with carboxylic acid and / or carboxylic anhydride, polarity is imparted to the hot melt adhesive, so that the essential wettability is improved. As a result, it is considered that the wet adhesiveness is improved.

  The hot melt adhesive of the present invention comprises (B) a wax, but considering the results of Comparative Example 5, the wet adhesion is improved with a smaller amount. Since the (B) wax exerts its effect with a smaller addition amount, when using the (B) wax, the dry adhesive properties to the synthetic rubber hot melt as the base polymer, thermal stability, odor, raw material cost, etc. It is understood that the influence is small and only wet adhesion can be improved very effectively.

(B) The wax can exert an effect with a small blending amount, such as styrene-isoprene block copolymer, styrene-butadiene block copolymer, hydrogenated styrene-isoprene block copolymer, hydrogenated styrene-butadiene block copolymer, polyolefin, etc. Since it is compatible with almost all thermoplastic elastomers, any base polymer can be used to provide an effect of improving wet adhesion.
Therefore, according to the present invention, (B) a method for producing a hot-melt adhesive having improved wet adhesion using a wax, and (B) a wet-adhesion improving agent for a hot-melt adhesive containing a wax Can also be provided. Based on these findings, the present invention can design and impart a wide variety of physical properties to the hot melt adhesive.

In general, in the field of assembling disposable products such as disposable diapers, in order to maintain the absorbability of bodily fluids, wet adhesion to natural water-immersed materials such as tissues and cotton sheets is required. Various performances are required depending on the parts used, such as dry adhesion and creep resistance. In designing a hot-melt adhesive that meets these various requirements, the technique of the present invention can be an effective improvement means.

Claims (5)

(A) a thermoplastic block copolymer that is a copolymer of a vinyl aromatic hydrocarbon and a conjugated diene compound, and (B) a wax modified with a carboxylic acid and / or a carboxylic anhydride. A hot melt adhesive for disposable products . (A) The thermoplastic block copolymer comprises a styrene-isoprene block copolymer (SIS), a styrene-butadiene block copolymer (SBS), a hydrogenated styrene-isoprene block copolymer (SEPS), and a hydrogenated styrene-butadiene block. The hot-melt adhesive for disposable products according to claim 1, which is at least one selected from copolymers (SEBS). The hot melt adhesive for disposable products according to claim 1 or 2, wherein (B) the wax modified with carboxylic acid and / or carboxylic anhydride is a polyolefin wax modified with maleic acid and / or maleic anhydride. . Furthermore, (C) a tackifier resin and (D) a plasticizer are included, and the total of (A) thermoplastic block copolymer, (C) tackifier resin and (D) plasticizer is 100 parts by weight, (A ) 10-35 parts by weight of thermoplastic block copolymer, (B) 0.3-5.0 parts by weight of wax modified with carboxylic acid and / or carboxylic anhydride, (C) 45-80 parts by weight of tackifying resin The hot melt adhesive for disposable products according to any one of claims 1 to 3, comprising 3 parts by weight of (D) plasticizer. A disposable product obtained by applying the hot melt adhesive for disposable products according to any one of claims 1 to 4.