JP6671415B2 - Hot melt adhesive - 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.

Used in disposable products such as diapers and napkins, its base material, for example, as a hot melt adhesive applied to nonwoven fabrics, tissues and polyethylene films, etc. Melt adhesives are widely used.
When manufacturing disposable products, a hot-melt adhesive is applied to a film or a nonwoven fabric, but high-speed coating may be used to increase the production efficiency of disposable products. However, the synthetic rubber-based hot melt adhesive may be scattered when applied at a high speed.

As one of means for improving the production efficiency of disposable products, there is a method of applying an olefin hot melt adhesive represented by an ethylene-propylene copolymer at a high speed.
Patent Documents 1 to 3 disclose hot melt adhesives containing an olefin polymer as a main component. Olefin-based hot melt adhesives are generally known to be more suitable for paper processing applications than disposable products.

  Patent Literature 1 describes that a propylene polymer is used as a raw material for a hot-melt adhesive (see Patent Literature 1, Claim 14, etc.). Absent. Many diapers and napkins have a structure in which an absorbent body composed of pulp and an absorbent polymer is wrapped in a tissue, and the outside thereof is covered with a nonwoven fabric, a polyethylene film, or the like. Therefore, hot melt adhesives for disposable products are required to have high adhesive strength to polyethylene films.

  Patent Document 2 discloses a polyolefin-based hot melt adhesive for disposable products (see Patent Document 2 [0001] and [0041], etc.). When spirally applying the hot melt adhesive of Patent Document 2 to a polyethylene film, it is necessary to increase the application temperature and decrease the viscosity in order to cope with a complicated application pattern. As shown in Table 1 of Patent Document 2, the coating temperature of the hot melt adhesive is set to a high temperature (350 ° F. to 365 ° F.). However, when the hot melt adhesive is applied to the polyethylene film at the above temperature, the film is melted by heat, or the coated hot melt adhesive cools and shrinks, causing wrinkles in the film.

  Patent Document 3 discloses a propylene-based hot melt adhesive (see Patent Document 3, Claims, etc.). However, similarly to the hot melt adhesive of Patent Document 2, it is difficult to perform spiral coating at low temperature, and the hot melt adhesive of Patent Document 3 cannot be said to have sufficient peel strength between nonwoven fabrics.

Re-publication 2003-87172 JP-T-2003-533551 JP 2003-518171 A

  An object of the present invention is to provide a hot-melt adhesive excellent in high-speed coating and spiral coating at low temperatures, and also excellent in adhesion to polyethylene and nonwoven fabric, and a disposable product obtained by the hot-melt adhesive. I do.

  The present inventors have conducted intensive studies and found that, when an ethylene copolymer is blended with a propylene homopolymer having a narrow molecular weight distribution and a low melting point, it is excellent in high-speed coating and excellent in spiral coating at a low temperature. Found that a hot-melt adhesive excellent in adhesion to polyethylene and nonwoven fabric was obtained, and found that such a hot-melt adhesive was suitable for disposable products, and completed the present invention. .

  Furthermore, it has been found that when the ethylene-based copolymer, which is a component of the hot melt adhesive, is an ethylene / octene copolymer, the coating pattern of the hot melt adhesive becomes inconspicuous and the appearance of the disposable product is improved.

  That is, the present invention provides a hot melt adhesive comprising (A) a propylene homopolymer having a melting point of 100 ° C. or lower and obtained by polymerizing propylene using a metallocene catalyst, and (B) an ethylene-based copolymer. .

The present invention provides, in one aspect, a hot melt adhesive which is an ethylene / α-olefin copolymer obtained by polymerizing (B) an ethylene-based copolymer using a metallocene catalyst.
As a preferred embodiment of the present invention, there is provided a hot melt adhesive, wherein (B) the ethylene / α-olefin copolymer comprises at least one selected from ethylene / propylene and ethylene / octene copolymer.

In another aspect, the present invention provides a hot melt adhesive containing (C) a tackifier resin and (D) an oil.
The present invention provides, as a further aspect, a hot melt adhesive comprising (E) a wax, wherein the (E) wax has a wax modified with a carboxylic acid and / or a carboxylic anhydride.

The present invention provides, as a further preferred embodiment, a hot melt adhesive having a melt viscosity at 150 ° C. of 7000 mPa · s or less.
According to a second aspect of the present invention, there is provided a disposable product obtained by using the hot melt adhesive.

  Since the hot melt adhesive of the present invention contains (A) a propylene homopolymer having a melting point of 100 ° C. or less and obtained by polymerizing propylene using a metallocene catalyst, and (B) an ethylene-based copolymer, Excellent in coating and spiral coating at low temperature, and excellent in adhesion to polyethylene film and non-woven fabric.

  When the (B) ethylene copolymer is an ethylene / α-olefin copolymer obtained by polymerization using a metallocene catalyst, the hot melt adhesive of the present invention is suitable for high-speed coating and spiral coating at low temperature. Superior in adhesion to polyethylene film and non-woven fabric while maintaining suitability.

  In the hot melt adhesive of the present invention, when (B) the ethylene / α-olefin copolymer contains at least one selected from ethylene / propylene copolymer and ethylene / octene copolymer, the suitability for spiral coating at low temperatures is further improved. In the case of containing an ethylene / octene copolymer, the coating pattern when spirally applied to an adherend such as a polyethylene film or a nonwoven fabric becomes inconspicuous.

When the hot melt adhesive of the present invention further contains (C) a tackifying resin and (D) an oil, while maintaining suitability for high-speed coating or spiral coating at a low temperature, the hot-melt adhesive with a polyethylene film or nonwoven cloth can be used. Adhesion is further improved.
The hot melt adhesive of the present invention contains (E) a wax, and when the (E) wax has a wax modified with a carboxylic acid and / or a carboxylic anhydride, it is suitable for high-speed coating and low-temperature spiral coating. The adhesiveness to polyethylene film and non-woven cloth is further improved while maintaining the suitability of the resin.

When the hot melt adhesive of the present invention has a melt viscosity at 150 ° C. of 7000 mPa.s or less, low-temperature spiral coating at about 150 ° C. becomes possible, and a film as an adherend becomes difficult to melt at a high temperature. The film hardly shrinks even when the temperature of the bonding portion of the film decreases.
Since the disposable product of the present invention is obtained by the hot melt adhesive, it can be efficiently manufactured on a high-speed coating line, and the coating line has a low temperature of about 150 ° C., so that the safety is high, and the nonwoven fabric or film can be peeled off. Moreover, the coating pattern is hardly conspicuous and the appearance is excellent.

  The hot melt adhesive according to the present invention comprises (A) a propylene homopolymer having a melting point of 100 ° C. or lower obtained by polymerizing propylene using a metallocene catalyst, and (B) an ethylene copolymer. Contains as an essential component.

  In the present invention, the propylene homopolymer (A) is a homopolymer of propylene, which is produced using a metallocene catalyst as a polymerization catalyst. (A) The melting point of the propylene homopolymer is 100 ° C. or lower, more preferably 60 to 90 ° C., and most preferably 65 to 85 ° C.

  Melting point refers to a value measured using differential scanning calorimetry (DSC). Specifically, 10 mg of a sample is weighed in an aluminum container using DSC6220 (trade name) manufactured by SII Nanotechnology and measured at a heating rate of 5 ° C./min. The temperature at the top of the melting peak is called the melting point.

When propylene is polymerized using a metallocene catalyst, (i) a propylene homopolymer having crystallinity and (ii) having a very narrow molecular weight distribution is synthesized.
(I) means that complete isotacticity and syndiotacticity can be arbitrarily controlled. Therefore, a polymer having a uniform arrangement and ratio of methyl groups can be obtained without causing a bias in the crystallinity, and a low crystallinity site which causes a decrease in adhesion is unlikely to be generated.

  Regarding (ii), the degree of molecular weight distribution of (A) the propylene homopolymer is represented by a polydispersity (Mw / Mn) of 1.0 to 3.0. A propylene homopolymer having a polydispersity of 1.0 to 3.0 has excellent adhesive strength. The molecular weight distribution is a concept indicating the distribution of the molecular weight of the synthetic polymer, and the ratio between the weight average molecular weight (Mw) and the number average molecular weight (Mn) (polydispersity: Mw / Mn) is used as a measure. In the present invention, the measurement of the molecular weight distribution is performed by gel permeation chromatography (GPC).

Examples of the (A) propylene homopolymer include (A1) a propylene homopolymer having a weight average molecular weight of 60,000 or less, and (A2) a propylene homopolymer having a weight average molecular weight of more than 60,000.
(A1) The weight average molecular weight of the propylene homopolymer is preferably from 30,000 to 60,000, and particularly preferably from 30,000 to 55,000.

(A2) The propylene homopolymer has a weight average molecular weight of more than 60,000, and particularly preferably has a weight average molecular weight of more than 60,000 and 90,000 or less, more preferably more than 60,000 and 80,000 or less.
(A1) Elmodu X400S (trade name) manufactured by Idemitsu Kosan Co., Ltd. can be exemplified as a commercial product of propylene homopolymer, and (A2) Elmodu X600S (trade name) manufactured by Idemitsu Kosan Co., Ltd. can be exemplified as a commercial product of propylene homopolymer.

In the present invention, (A) the propylene homopolymer preferably contains (A1) a propylene homopolymer, but may further contain (A2).
Further, (A) the propylene homopolymer may not include the (A1) propylene homopolymer, but may include only the (A2) propylene homopolymer.

In the present invention, the propylene homopolymer (A) is preferably 60 to 95 parts by weight, and more preferably 70 to 95 parts by weight, based on 100 parts by weight of the total of the propylene homopolymer (A) and the ethylene copolymer (B). Preferably it is 90 parts by weight.
When the (A) propylene homopolymer contains both (A1) propylene homopolymer and (A2) propylene homopolymer, the weight ratio of both polymers is 1: 3 to 3: 2 ((A1) :( A2)). Is preferred.

The weight average molecular weight (Mw) means a value measured by gel permeation chromatography (GPC). Specifically, the value can be measured using the following apparatus and measuring method. Waters RI is used as a detector. As a GPC column, TSKGEL GMHHR-H (S) HT manufactured by Tosoh Corporation is used. A sample is dissolved in 1,2,4-trichlorobenzene, the flow rate is 1.0 ml / min, the measurement temperature is 145 ° C., the molecular weight is converted using a calibration curve with polypropylene, and the weight average molecular weight is determined. .
Since the number average molecular weight (Mn) is also obtained by the same method, the molecular weight distribution is also calculated by GPC.

  Since the hot melt adhesive of the present invention contains (A1) a propylene homopolymer, the suitability for spiral coating at low temperatures is improved while maintaining the adhesive strength to a polyethylene film or a nonwoven fabric.

  In the present invention, the (B) ethylene-based copolymer refers to a copolymer of ethylene and a copolymerizable monomer copolymerizable with ethylene.

As the copolymerizable monomer,
Α-olefins such as ethylene, propylene, octene and butene;
Carboxylic acids (esters) such as vinyl acetate, (meth) acrylic acid, (meth) acrylic acid ester, maleic acid, and maleic acid ester;
Carboxylic anhydrides such as maleic anhydride, phthalic anhydride and succinic anhydride;
Etc. can be exemplified.

  These copolymerizable monomers may be copolymerized with ethylene alone, or two or more copolymerizable monomers may be copolymerized.

  In this specification, (meth) acrylic acid refers to a concept including both methacrylic acid and acrylic acid. Specific examples of the (meth) acrylate include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, and acryl. Examples thereof include isooctyl acid, methyl methacrylate, ethyl methacrylate, and glycidyl methacrylate.

  Therefore, in the present invention, as the ethylene copolymer (B), ethylene / α-olefin copolymer, ethylene / carboxylic acid copolymer, ethylene / carboxylic acid ester copolymer, and ethylene / carboxylic anhydride copolymer are used. Can be illustrated.

As the ethylene copolymer (B) of the present invention, an ethylene / α-olefin copolymer is preferred. As the ethylene / α-olefin copolymer, an ethylene / α-olefin copolymer obtained by polymerization with a metallocene catalyst is particularly preferable.
When the hot melt adhesive of the present invention contains an ethylene / α-olefin copolymer obtained by polymerization with a metallocene catalyst, the suitability for spiral coating at low temperatures is improved, and the adhesion to a polyethylene film or a nonwoven fabric is further improved. .

Examples of the ethylene / α-olefin copolymer obtained by polymerization with a metallocene catalyst include ethylene / propylene copolymer, ethylene / octene copolymer, ethylene / butene copolymer, ethylene / propylene / butene, and particularly ethylene / propylene copolymer, ethylene / Octene is preferred.
When the hot melt adhesive of the present invention contains at least one selected from ethylene / propylene copolymer and ethylene / octene, the suitability for spiral coating at low temperatures is further improved.

  The ethylene / propylene copolymer preferably has a melt index at 230 ° C. of 200 g / 10 min or less, more preferably 10 to 50 g / 10 min, and most preferably 20 to 30 g / 10 min. When the melt index is within the above range, the peel strength of the hot melt adhesive is improved.

  In the present specification, the melt index means an index indicating the fluidity of the resin, and a fixed amount of synthetic resin is heated at a predetermined temperature (for example, 230 ° C.) in a cylindrical container heated by a heater. It is indicated by the amount of resin extruded per 10 minutes from an opening (nozzle) provided at the bottom of the container by applying pressure under a predetermined load (for example, 2.16 kg). Unit: g / 10 min is used. It is measured by the measurement method specified in ASTM D1238.

  A hot melt adhesive containing an ethylene / octene copolymer can improve the appearance of a disposable product because the coating pattern is inconspicuous even when spirally applied to an adherend such as a polyethylene film or a nonwoven fabric.

  As a preferred embodiment of the present invention, in the case of (B) an ethylene / propylene copolymer obtained by polymerizing an ethylene-based copolymer with a metallocene catalyst, (A) a propylene homopolymer is (A1) a propylene homopolymer and (A2) a propylene homopolymer. It is preferred to include both homopolymers. When the components (A) and (B) are in the above-mentioned combination, the peel strength of the hot melt adhesive is remarkably improved.

  In another preferred embodiment of the present invention, when (B) an ethylene / octene copolymer obtained by polymerizing an ethylene-based copolymer with a metallocene catalyst, (A) a propylene homopolymer contains only (A1) a propylene homopolymer. Is preferred. When the component (A) and the component (B) are in the above-mentioned combination, the coating pattern of the hot melt adhesive becomes almost inconspicuous, and the appearance of the disposable product is remarkably improved.

  The ethylene / octene copolymer is preferably a block copolymer, rather than a random copolymer. When the ethylene / octene copolymer is a block copolymer, a hot melt adhesive having excellent peel strength can be obtained.

The hot melt adhesive for disposable products of the present invention preferably further contains (C) a tackifier resin. (C) The tackifier resin is preferably blended in an amount of 20 to 180 parts by weight, more preferably 40 to 150 parts by weight, based on 100 parts by weight of the total of (A) the propylene homopolymer and (B) the ethylene copolymer. it is more preferable to be parts by weight blended, it is particularly preferred that the blending 60 to 150 parts by weight.
By mixing the (C) tackifying resin in the above ratio, the hot melt adhesive can be spirally coated at a low temperature of 150 ° C. or lower, and can be uniformly coated on a polyethylene film or a nonwoven fabric. , Making it more suitable for the production of disposable products.

  (C) Examples of the tackifying resin 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, hydrogenated rosin Pentaerythritol ester, natural terpene copolymer, natural terpene three-dimensional polymer, hydrogenated derivative of hydrogenated terpene copolymer, polyterpene resin, hydrogenated derivative of phenolic modified terpene resin, aliphatic petroleum hydrocarbon resin, aliphatic petroleum Examples thereof include hydrogenated derivatives of hydrocarbon resins, aromatic petroleum hydrocarbon resins, hydrogenated derivatives of aromatic petroleum hydrocarbon resins, cycloaliphatic petroleum hydrocarbon resins, and hydrogenated derivatives of cycloaliphatic petroleum hydrocarbon resins. it can. These tackifier resins can be used alone or in combination. As the tackifier resin, a liquid-type tackifier resin can be used as long as the color tone is colorless to pale yellow and there is substantially no odor and good thermal stability. Considering these characteristics comprehensively, a hydrogenated derivative such as a resin is preferred as the tackifying resin, and a hydrogenated dicyclopentadiene-based resin is particularly desirable.

  (C) A commercial product can be used as the tackifier resin. Examples of such commercially available products include Alcon P100 (trade name) and Alcon M100 (trade name) manufactured by Arakawa Chemical Co., Ltd., Clearon M105 (trade name) manufactured by Yashara Chemical Co., Ltd., ECR5400 (trade name) manufactured by Exxon, and ECR179EX (trade name). (Trade name) and Quinton DX390 (trade name) manufactured by Zeon Corporation. These commercially available tackifying resins can be used alone or in combination.

Further, the hot melt adhesive of the present invention can contain (D) oil. (D) The oil is blended as a plasticizer for the purpose of lowering the melt viscosity of the hot melt adhesive, imparting flexibility, and improving wettability to an adherend. (D) Spiral coating at low temperature becomes possible by blending oil,
Examples of the (D) oil include paraffinic oils, naphthenic oils, and aromatic oils.

  (D) Commercial products can be used as the oil. For example, Diana Fresia S32 (trade name) manufactured by Idemitsu Kosan Co., Ltd., Diana Process Oil PW-90 (trade name), Process Oil NS-100 (trade name), Fazol 35 (trade name) manufactured by SK LUBRICANTS, PetroChina KN4010 (trade name), Kukdong Oil & Chem White Oil Brom 350 (trade name), DN Oil KP-68 (trade name), BP Chemicals EnperperM1930 (trade name), Crompton Kaydol (trade name) ) And Primol 352 (trade name) manufactured by Esso. These (D) oils can be used alone or in combination.

  The hot melt adhesive of the present invention preferably contains (E) a wax. As used herein, the term "wax" refers to an organic substance having a weight average molecular weight of less than 10,000 that becomes a solid at room temperature and becomes a liquid when heated, and is generally referred to as a "wax". Is not particularly limited as long as the hot melt adhesive according to the present invention can be obtained.

(E) The wax preferably contains (E1) an olefin wax modified with a carboxylic acid or a carboxylic anhydride.
In the present invention, “(E1) olefin wax modified with carboxylic acid or carboxylic anhydride” refers to an olefin wax chemically or physically processed with carboxylic acid or carboxylic anhydride. Is not particularly limited as long as the desired hot melt adhesive can be obtained. Examples of chemical and physical processing include, for example, oxidation, polymerization, compounding, and synthesis.

Examples of the (E1) wax include, for example, a wax obtained by graft-polymerizing a carboxylic acid or a carboxylic anhydride to an olefin wax; and a carboxylic acid or a carboxylic anhydride when the olefin wax is synthesized by polymerization. A wax obtained by copolymerization can be exemplified.
Thus, using various reactions, carboxylic acids or carboxylic anhydrides may be introduced into the "olefin wax" resulting in a modified olefin wax.

The “carboxylic acid” and / or “carboxylic anhydride” for modifying the olefin wax is not particularly limited as long as the hot melt adhesive of the present invention can be obtained.
Specific examples of the carboxylic acid or carboxylic anhydride include, for example, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, itaconic acid, acrylic acid and methacrylic acid. These carboxylic acids and / or carboxylic anhydrides may be used alone or in combination. Maleic acid and maleic anhydride are preferred, and maleic anhydride is particularly preferred.

  The “olefin wax” modified with a carboxylic acid or a carboxylic anhydride refers to a wax obtained by copolymerizing two or more olefins, as long as the (E1) wax targeted by the present invention can be obtained. However, there is no particular limitation. Therefore, a wax in which one kind of olefin is homopolymerized is not included in the olefin wax.

Specific examples of the olefin wax include polyethylene wax, polypropylene wax, polyethylene / polypropylene wax, polyethylene / polybutylene wax, and polyethylene / polybutene wax.
Accordingly, a polyolefin wax modified with maleic anhydride is particularly preferred as the (E1) wax in the present invention.

The “(E) wax” can include a base wax in addition to the (E1) wax. As such a base wax, specifically, for example,
Synthetic waxes such as Fischer-Tropsch wax, polyolefin wax (eg, polyethylene wax, polypropylene wax, polyethylene / polypropylene wax);
Petroleum waxes such as paraffin wax and microcrystalline wax;
Examples include natural waxes such as caster wax.

The above-mentioned base wax may be modified. As the substance to be modified, various carboxylic acid derivatives may be used as long as a polar group can be introduced. Examples of such "carboxylic acid derivatives" include the following:
Carboxylic esters 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.
The modified base wax does not include (E1) olefin wax modified with carboxylic acid or carboxylic anhydride.

  In the present invention, the (E) wax preferably contains (E2) Fischer-Tropsch wax described as the base wax in addition to (E1). "(E2) Fischer-Tropsch wax" refers to one synthesized by the Fischer-Tropsch method and generally referred to as Fischer-Tropsch wax. Fischer-Tropsch wax is obtained by fractionating wax from component waxes having a relatively wide carbon number distribution so that component molecules have a narrow carbon number distribution. Representative examples of Fischer-Tropsch wax include Sasol H1 (trade name) and Sasol C80 (trade name), all of which are commercially available from Sasol Wax.

In the present invention, the melting point of the wax (E1) is preferably from 100 to 130 ° C., and the melting point of the base wax, preferably (E2), is preferably from 60 to 90 ° C. The method for measuring the melting point is the same as the method for measuring the melting point of the component (A).
(E) The wax preferably has an acid value of 5 to 200 mgKOH / g, more preferably 20 to 160 mgKOH / g. The acid value can be measured by a method according to ASTM D1308 or BWM 3.01A.

The hot melt adhesive according to the present invention may further contain various additives as necessary. Examples of such various additives include a stabilizer and a fine particle filler.
The term "stabilizer" is used to prevent the molecular weight of the hot melt adhesive from being lowered by heat, gelation, coloring, generation of odor, etc., and to improve the stability of the hot melt adhesive. There is no particular limitation as long as the hot melt adhesive intended by the present invention can be obtained. Examples of the "stabilizer" include, for example, an antioxidant and an ultraviolet absorber.

  "Ultraviolet absorbers" are used to improve the light fastness of hot melt adhesives. "Antioxidants" are used to prevent oxidative degradation of hot melt adhesives. The antioxidant and the ultraviolet absorber are generally used for disposable products, and can be used as long as the intended disposable product described below can be obtained, and are particularly limited. is not.

  Examples of the antioxidant include a phenolic antioxidant, a sulfur-based antioxidant, and a phosphorus-based antioxidant. Examples of the ultraviolet absorber include a benzotriazole-based ultraviolet absorber and a benzophenone-based ultraviolet absorber. Further, a lactone stabilizer can be added. These can be used alone or in combination.

  Commercially available products can be used as stabilizers. 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) manufactured by Ciba Specialty Chemicals, and Irganox HP2225FF (trade name) Trade name), Irgafoss 168 (trade name), Irganox 1520 (trade name), and JF77 (trade name) manufactured by Johoku Chemical Co., Ltd. can be exemplified. These stabilizers can be used alone or in combination.

  The hot melt adhesive for disposable products of the present invention can further include a particulate filler. The fine particle filler is not particularly limited as long as it is generally used, as long as 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 their dimensions (diameter if spherical) are not particularly limited.

  The hot melt adhesive for disposable products of the present invention comprises the components (A) and (B), and optionally the components (C) to (E), and optionally various additives. It can be manufactured by heating, melting and mixing. Specifically, it can be produced by putting the above-mentioned components into a melt-mixing kettle equipped with a stirrer and mixing by heating.

  The hot melt adhesive for disposable products according to the present invention preferably has a melt viscosity at 150 ° C of 7000 mPa · s or less, more preferably 1000 to 6000 mPa · s, and more preferably 2000 to 6000 mPa · s. Particularly preferred. The “melt viscosity” is the viscosity of the melt of the hot melt adhesive, and is measured by a Brookfield RVT viscometer (Spindle No. 27).

When the melt viscosity is controlled within the above range, the hot melt adhesive is more suitable for low-temperature coating, and is further uniformly applied to a nonwoven fabric and easily penetrates, so that it is more suitable for disposable products.
As described above, the hot melt adhesive according to the present invention can be used for paper processing, bookbinding, disposable products, and the like.However, since it has excellent adhesiveness to nonwoven fabrics and polyethylene films, it is suitably used for disposable products. You.

  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, nonwoven fabric, rubber, resin, paper, and polyolefin film. The polyolefin film is preferably a polyethylene film for reasons such as durability and cost.

The disposable product is not particularly limited as long as it is a so-called sanitary material. Specific examples include disposable diapers, sanitary napkins, pet sheets, hospital gowns, surgical lab coats, and the like.
In a disposable product manufacturing line, a hot melt adhesive is generally applied to various members (for example, tissue, cotton, nonwoven fabric, polyolefin film, etc.) of the disposable product. During application, the hot melt adhesive may be spouted from various jets and used.

  The method for applying the hot melt adhesive is not particularly limited as long as the intended disposable product can be obtained. Such coating methods are roughly classified into contact coating and non-contact coating. "Contact application" refers to a method of applying a jetting machine to a member or a film when applying a hot melt adhesive, and "non-contact application" refers to a method for applying a hot melt adhesive when applying a hot melt adhesive. It refers to a coating method that does not contact members or films. Examples of the contact coating method include slot coater coating and roll coater coating, and examples of the non-contact coating method include spiral coating that can be applied spirally, omega coating that can be applied in a wavy form, 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 dot shape.

  The hot melt adhesive of the present invention is suitable for spiral coating. Spiral coating is a method of applying an adhesive intermittently or continuously, sending air to form a spiral adhesive, and applying the adhesive to a member (or base material). Refers to a method of non-contact coating.

  The ability to apply the hot melt adhesive over a wide range by spray coating is extremely advantageous for producing disposable products. The hot melt adhesive which can be applied in a wide width can adjust the coating width to be narrow by adjusting the pressure of hot air.

If the hot melt adhesive is difficult to apply due to its wide width, a large number of spray nozzles are required to obtain a sufficient bonding area, and relatively small disposable products such as urine absorbing liners and disposable products with complicated shapes It is disadvantageous to manufacture.
Therefore, the hot melt adhesive of the present invention is suitable for disposable products since it can be spirally applied over a wide range.

  The hot melt adhesive of the present invention has good coating suitability at 150 ° C. or lower, and is therefore useful for producing disposable products. When the hot melt adhesive is applied at a high temperature, the polyethylene film which is the base material of the disposable product is melted or thermally contracted, so that the appearance of the disposable product is greatly impaired. When the hot melt adhesive is applied at a temperature of 150 ° C. or lower, the appearance of the polyethylene film or the nonwoven fabric, which is the base material of the disposable product, hardly changes, and the appearance of the product is not impaired.

  The hot melt adhesive of the present invention is suitable for producing disposable products in a short time because it is excellent in high-speed coating suitability. When a hot-melt adhesive is applied to a substrate conveyed at a high speed, the contact-type application method may cause breakage of the substrate due to friction. Since the hot melt adhesive of the present invention is suitable for spiral coating, which is a type of non-contact coating, it is suitable for high-speed coating and can improve the production efficiency of disposable products. Further, the hot melt adhesive of the present invention suitable for high-speed coating minimizes disturbance of the coating pattern.

  The hot melt adhesive of the present invention has good thermal stability, is uniformly melted in a high-temperature tank at 100 to 200 ° C., and does not undergo phase separation. A hot melt adhesive having poor thermal stability easily undergoes phase separation in a high-temperature tank. The occurrence of such phase separation may cause clogging of the tank filter, the transport piping, and the like.

The main aspects of the present invention are shown below.
1. A hot melt adhesive comprising (A) a propylene homopolymer having a melting point of 100 ° C. or lower and obtained by polymerizing propylene using a metallocene catalyst, and (B) an ethylene-based copolymer.
2. (B) The hot melt adhesive according to the above item 1, wherein the ethylene copolymer is an ethylene / α-olefin copolymer obtained by polymerization using a metallocene catalyst.
3. (B) The hot melt adhesive according to the above item 2, wherein the ethylene / α-olefin copolymer includes at least one selected from an ethylene / propylene copolymer and an ethylene / octene copolymer.
4. The hot melt adhesive according to any one of the above items 1 to 3, further comprising (C) a tackifier resin and (D) an oil.
5. The hot melt adhesive according to any one of the above items 1 to 4, further comprising (E) a wax, wherein the (E) wax has a wax modified with a carboxylic acid and / or a carboxylic anhydride.
6. The hot melt adhesive according to any one of the above items 1 to 5, which has a melt viscosity at 150 ° C of 7000 mPa · s or less.
7. A disposable product obtained by the hot melt adhesive according to any one of the above 1 to 6.

Hereinafter, the present invention will be described with reference to Examples for the purpose of describing the present invention in more detail and more specifically. These examples serve to illustrate the invention and do not limit the invention in any way.
The components for blending the hot melt adhesive are shown below.

(A) A propylene homopolymer having a melting point of 100 ° C. or lower obtained by polymerization with a metallocene catalyst. (A1) Idemitsu Kosan Co., Ltd. product name “Elmodu X400S”
Melting point 75 ° C weight average molecular weight 45,000
(A2) Idemitsu Kosan Co., Ltd. product name "Elmodu X600S"
Melting point 80 ° C Weight average molecular weight 70000
(A'3) Product name “Ricosen PP6102” manufactured by Clariant
Propylene homopolymer obtained by polymerization with metallocene catalyst
145 ° C
(A'4) Eastman Chemical Company's product name "Eastflex P1010"
Propylene homopolymer obtained by polymerization with Ziegler-Natta catalyst
145 ° C
(A'5) Product name "Ricosen PE4201GR" manufactured by Clariant
Polyethylene homopolymer obtained by polymerization with metallocene catalyst
Melting point 128 ° C

(B) Ethylene copolymer (B1) Trade name “Vistamax 2330” manufactured by ExxonMobil
Propylene / ethylene copolymer obtained by polymerization with metallocene catalyst
Melt index 200 (g / 10min: 230 ° C)
(B2) ExxonMobil's product name "Vistamax 6202"
Propylene / ethylene copolymer obtained by polymerization with metallocene catalyst
Melt index 20 (g / 10min: 230 ° C)
(B3) Dow's product name "Versify 4301"
Propylene / ethylene copolymer obtained by polymerization with metallocene catalyst
Melt index 25 (g / 10min: 230 ° C)
Propylene / ethylene random copolymer structure (B4) Product name “Infuse 9807” manufactured by Dow
Ethylene / octene copolymer obtained by polymerization with metallocene catalyst
Melt index 15 (g / 10min: 190 ° C)
Having a block structure of ethylene / octene (B5) Product name “Engage 8137” manufactured by Dow
Ethylene / octene copolymer obtained by polymerization with metallocene catalyst
Melt index 13 (g / 10min: 190 ° C)
Ethylene / octene random copolymer structure (B6) Product name “Affinity GA1950” manufactured by Dow
Ethylene / octene copolymer obtained by polymerization with metallocene catalyst
Melt index 500 (g / 10min: 190 ° C)
Ethylene / octene random copolymer structure (B7) Huntsman's product name “Rexcentac 2780A”
Propylene / ethylene copolymer obtained by polymerization with Ziegler-Natta catalyst (B8) Product name “Bestplast 703” manufactured by Evonik
Propylene / ethylene / butene copolymer obtained by polymerization with Ziegler-Natta catalyst (B9) Trade name “Ultracene 722” manufactured by Tosoh Corporation
Ethylene / vinyl acetate copolymer obtained by polymerizing with Ziegler-Natta catalyst (B'10) manufactured by Huntsman Corporation "Rexentac 2780A"
Propylene / butene copolymer obtained by polymerization with Ziegler-Natta catalyst (B'11) Trade name "BR-106" manufactured by Mitsubishi Rayon Co., Ltd.
Acrylic copolymer

(C) Tackifying resin (C1) Hydrogenated dicyclopentadiene resin
ExxonMobil Corp. product name "ECR179EX"
(C2) Hydrogenated dicyclopentadiene resin
ExxonMobil's product name "ECR5400"
(C3) Hydrogenated cycloaliphatic petroleum hydrocarbon resin
Arakawa Chemical Co., Ltd. Product name “ALCON M100”
(C4) Hydrogenated cycloaliphatic petroleum hydrocarbon resin
Arakawa Chemical Co., Ltd. Product name "ALCON P100"
(C5) Unhydrogenated aliphatic / aromatic copolymer resin
Product name “Quinton DX390N” manufactured by Zeon Corporation
(C6) Hydrogenated terpene resin
Product name "Clearon M105" manufactured by Yashara Chemical

(D) Oil (D1) Paraffin oil Idemitsu Kosan Co., Ltd. Product name "DN Oil KP-68"
(D2) Paraffin oil SK LUBRICANTS product name “Fazol 35”
(D3) Paraffin oil Idemitsu Kosan Co., Ltd. Product name "Diana Process Oil PW-90"
(D4) Paraffin oil Idemitsu Kosan Co., Ltd. Product name "Diana Fresia S32"
(D5) Naphthenic oil "Process oil NS-100" manufactured by Idemitsu Kosan Co., Ltd.
(D6) Naphthenic oil "KN4010" manufactured by Petro China

(E) Wax modified with carboxylic acid and / or carboxylic anhydride (E1) Maleic acid-modified wax manufactured by Clariant “Licocene MA6252TP”
(E2) Fisher-Tropx Wax manufactured by Sasol Co., Ltd. "Sasol Wax H-1"

(F) Antioxidant (F1) Product name “ADEKA STAB AO-60” manufactured by ADEKA CORPORATION
Hindered phenolic antioxidants

The components (A) to (F) were blended at the ratios shown in Tables 1 to 3, and melted and mixed at about 150 ° C. for 2 hours using a universal stirrer. A melt adhesive was prepared. The numerical values relating to the composition (mixing) of the hot melt adhesive shown in Tables 1 to 3 are all parts by weight.
For each of the hot melt adhesives (Examples and Comparative Examples), the heat stability, coating suitability, high speed coating suitability, and peel strength of the hot melt adhesive were evaluated. Hereinafter, the outline of each evaluation will be described.

<Thermal stability>
The thermal stability was evaluated based on whether or not the hot melt adhesive undergoes phase separation.
Each hot melt adhesive was put in a glass bottle, and allowed to stand at a temperature of 150 ° C. for 6 hours, and the presence or absence of phase separation was visually checked. Each hot melt adhesive weighed 350-400 g and used a 450 ml glass bottle. The glass bottle containing the hot-melt adhesive was covered with an aluminum lid and allowed to stand in a dryer.
It was taken out after a predetermined time, and the presence or absence of phase separation was immediately confirmed by visual observation.
・ ・ ・: No phase separation was observed.
X: Phase separation was observed.

<Melt viscosity measurement (150 ° C)>
The viscosity at 150 ° C. of each hot melt adhesive was measured based on JAI7-1991, Method B. For the measurement, a Brookfield viscometer was used, and a No. 27 rotor was used.

<Coating suitability>
Apply a hot melt adhesive to the coated base material using Spiral Spray of Nordson Co., and make a laminate of this coated base material and the bonded base material, and evaluate the coating suitability, A sample for evaluating the peel strength described below was prepared. Both the coated substrate and the bonded substrate are polyethylene terephthalate (PET) films.
More specifically, the temperature of the hot melt tank and the spiral spray nozzle is 150 ° C., the temperature of the hot air is 180 ° C., the pressure of the hot air is 0.32 kgf / cm ² , and the discharge amount of the hot melt adhesive is 15 g / cm ² . Min (equivalent to a coating weight of 5 g / m ² ), the distance from the nozzle to the coating substrate is 35 mm, the transport speed of the substrate is 200 m / min, the open time is 0.21 second, and the press pressure after coating is 2 Under a condition of 0.0 kgf / cm, a hot melt adhesive was applied to the coating substrate to produce a laminate (PET film / PET film), and then the coating suitability was evaluated. The coating suitability was evaluated by checking the coating width of the spirally coated hot melt adhesive. The evaluation criteria are shown below.
◎ ・ ・ ・ The coating width is 15mm or more ○ ・ ・ ・ The coating width is 12mm or more and less than 15mm × ・ ・ ・ The coating width is less than 12mm

<High-speed coating suitability>
High-speed coating suitability was evaluated under the above-described coating suitability test conditions.
The test was performed using the same method as the method for evaluating coating suitability, except that the pressure of the hot air was changed to 0.45 kgf / cm ² . The high-speed coating suitability was visually evaluated. The evaluation criteria are as follows.
：: No scattering of hot melt adhesive was observed.
：: Slight scattering of the hot melt adhesive was observed.
X: The pattern was not obtained because the hot melt adhesive was scattered. Alternatively, the coating width of the hot melt adhesive was less than 15 mm.

<Peel strength>
Using the test conditions described in the high-speed coating suitability described above, a sample having a peel strength was prepared.
Purpose nonwoven fabric as coated substrate with (no SMS 15 g / ^{m 2} surface treatment), as a substrate bonding, (1) (no SMS 15 g / ^{m 2} surface treatment) general nonwoven fabric, (2 ) Two types of general-purpose polyethylene films (no embossing, 30 g / m ² without corona treatment) were used.
Samples were run at 23 ° C, 65% R.C. H. After curing for 24 hours or more under the same environment, a peeling test was performed under the same environment. The peel test was carried out using an Autograph AGS-J manufactured by Shimadzu Corporation under the following conditions.
Peeling direction: the same direction (MD) as the substrate advance, the distance between the chucks: 20 mm, the peeling speed: 300 mm / min, the peeling length: 50 mm, the analysis method: the average test force The peeling strength was determined for each hot melt adhesive (Example and Example). For Comparative Example), at least three samples were prepared and measured, and the average value obtained showed the peel strength. Peel strength was evaluated according to the following criteria

(1) Non-woven cloth (nonwoven / nonwoven)
A: Peel strength of 2.0 N or more
：: Peel strength of 0.5 N or more and less than 2.0 N
×: Peel strength is less than 0.5N (2) The bonding substrate is a polyethylene film (polyethylene film / nonwoven fabric)
A: Peel strength of 0.20 N or more
：: Peel strength of 0.10 N or more and less than 0.20 N
×: Peel strength less than 0.10 N

<Appearance>
When the hot melt adhesive is applied to a breathable polyethylene film, the coating pattern of the hot melt adhesive applied inside may be seen through the surface of the film. A hot-melt adhesive with a conspicuous coating pattern is not preferred from the viewpoint of the design of a disposable product using a breathable film, and a hot-melt adhesive with a conspicuous coating pattern is desired.
The following method was used to evaluate whether the coating pattern was conspicuous.

Each hot-melt adhesive was applied to a PET film having a thickness of 50 μm to form an adhesive layer having a thickness of 50 μm, which was formed into a specimen having a size of 25 × 10 mm. The test body is bonded to a commercially available ventilated napkin (Eris, new skin feeling, 20.5 cm without feathers, manufactured by Elaire Papertech Co., Ltd.), a 1 kg weight is placed on the bonded portion, and placed in a dryer at 50 ° C. for 3 days. did. After a predetermined time, the weight was removed and the change in appearance was confirmed. The evaluation criteria are as follows.
◎ ・ ・ ・ The coated hot-melt adhesive is inconspicuous ○ ・ ・ ・ The coated hot-melt adhesive is slightly visible ×× ・ ・ ・ The coated hot-melt adhesive is transparent What you see

As shown in Table 1, the hot-melt adhesives of Examples 1 to 8 are excellent in heat stability, coating suitability, high-speed coating suitability, and also excellent in strength to nonwoven fabric, so that diapers, napkins, etc. It is suitable for disposable products using nonwoven fabrics.
On the other hand, as shown in Table 2, the hot melt adhesives of Comparative Examples 1 to 9 are inferior in any of the above performances.

  As shown in Table 3, the hot-melt adhesives of Examples 12 to 19 not only have the above-mentioned good performance, but also the pattern after coating is not conspicuous. Considering the design of a disposable product using a breathable film, the hot melt adhesives of Examples 12 to 19 are very excellent for disposable products.

  The present invention provides a hot melt adhesive. The hot melt adhesive according to the present invention is suitable for disposable products.

Claims (3)

(A) a propylene homopolymer having a melting point of 100 ° C. or less, obtained by polymerizing propylene using a metallocene catalyst;
(B) an ethylene copolymer;
(C) a tackifying resin;
Including
(B) the ethylene copolymer is an ethylene / α-olefin copolymer obtained by polymerization using a metallocene catalyst ;
The hot melt adhesive, wherein the ethylene / α-olefin copolymer comprises at least one selected from ethylene / propylene copolymer, ethylene / octene copolymer and ethylene / propylene / butene copolymer. The hot melt adhesive according to claim 1 , wherein the (B) ethylene / α-olefin copolymer includes at least one selected from ethylene / propylene copolymer and ethylene / octene copolymer. A disposable product obtained by using the hot melt adhesive according to claim 1 .