JP6539396B2 - Hot melt adhesive for containers with straw - Google Patents

Description

  The present invention relates to a hot melt adhesive for containers with a straw. More specifically, the present invention relates to a hot melt adhesive for bonding a plastic film for packaging a straw and a container (for example, a container made of paper, metal or plastic) filled with a beverage or the like.

  The container with a straw means the container with which the straw package obtained by accommodating the straw for attraction | suction in a plastic packaging bag was attached. Containers are generally often filled with beverages. Containers with straws are roughly classified by the material from which they are made. If the container is made of paper, a paper pack; if the container is made of metal, (metal) cans (more specifically, if it is made of aluminum, it can be aluminum can, if it is made of steel, it can be steel cans); If it is made of plastic such as polyethylene terephthalate, it is called a plastic cup or the like.

  Patent document 1 describes a (metal) can with a straw, and patent document 2 discloses a paper pack with a straw. Both documents describe attaching a straw package to a container using a hot melt adhesive.

The hot melt adhesive disclosed in Patent Document 1 is a styrene-butadiene-styrene block copolymer (SBS), a styrene-isoprene-styrene block copolymer (SIS), a styrene-ethylene / butylene-styrene block copolymer (SEBS) or a styrene-ethylene / propylene-styrene block copolymer (SEPS) -based hot melt adhesive (see Patent Document 1 [Claim 1] and [Example] etc.).
The hot melt adhesive of Patent Document 1 is a styrenic hot melt adhesive, which can be suitably used to attach a straw package to a metal container. However, the adhesive does not have sufficient adhesion to the paper container and is insufficient to stick the straw package to the paper container.

Patent Document 2 describes fixing a straw package to a container using a hot melt adhesive (see Patent Document 2 [0010] and the like).
However, in Patent Document 2, the composition of the hot melt adhesive used is completely unknown.

  Hot melt adhesives for containers with straws need to have excellent adhesion to plastic films such as polyolefins that package straws and substrates used to make containers, such as paper and plastic substrates . Furthermore, considering that the container to be manufactured is refrigerated, it is necessary that the hot melt adhesive has excellent adhesion at low temperatures (around 5 ° C.). In addition, hot melt adhesives are also required to have excellent water-resistant adhesion, since in the summer months condensation on the containers and containers with straws may be immersed in cold water.

  Thus, although the hot melt adhesive for containers with a straw is required to have various performances suitable for beverage container applications, no hot melt adhesive has been found which completely meets the demand of the consumer.

JP-A-5-162752 Japanese Patent Laid-Open No. 9-278066

  The present invention is excellent in adhesion to substrates such as paper and polyolefin, and also at low temperature (around 5 ° C.), and for adhering a straw package to a container made of the substrate It is an object of the present invention to provide a hot melt adhesive which is suitable and, in consideration of the handling of a container with a straw in the summer, also excellent in water-resistant adhesion.

  As a result of intensive studies, the present inventors have surprisingly found that a hot melt adhesive containing a diblock-type styrenic block copolymer can solve the above-mentioned problems, and completes the present invention It came to

The present invention is, in one summary,
(A) A hot melt adhesive comprising a thermoplastic block copolymer based on a vinyl aromatic hydrocarbon and a conjugated diene compound,
The thermoplastic block copolymer (A) provides a hot melt adhesive for containers with a straw, which comprises a styrenic block copolymer containing the component (A1): diblock copolymer.

In one embodiment of the present invention, the component (A1) is a hot block comprising a styrenic block copolymer having a styrene content of 20 to 50% by weight and a diblock copolymer content of 20 to 80% by weight. To provide a melt adhesive.
In another embodiment of the present invention, the (A) thermoplastic block copolymer provides a hot melt adhesive which further comprises the (A2) component: a triblock styrenic block copolymer.
In a preferred embodiment of the present invention, a hot melt adhesive is provided which further comprises (B) a tackifying resin, (C) a softener and (D) a wax.
In a further aspect of the invention, (C) the softener provides a hot melt adhesive comprising naphthenic oil and / or paraffinic oil.

In yet another aspect of the present invention, (D) the wax provides a hot melt adhesive comprising a Fischer-Tropsch wax.
Furthermore, in a preferred embodiment of the present invention, there is provided a hot melt adhesive comprising 3 to 30 parts by weight of (A1) per 100 parts by weight of the total weight of (A) to (D).
The present invention preferably provides a straw package affixed to a container with the above-mentioned hot melt adhesive and containing a straw, or a container with a straw in which the straw is held in the container with the above hot melt adhesive. be able to.

The hot melt adhesive of the present invention comprises a thermoplastic block copolymer based on vinyl aromatic hydrocarbon and a conjugated diene compound,
The thermoplastic block copolymer (A) contains a styrenic block copolymer containing the component (A1): diblock copolymer,
It is excellent in adhesion to substrates such as paper and polyolefin, and also excellent in adhesion at low temperatures (around 5 ° C.), and is suitable for producing a container with a straw.

  In the case of the hot melt adhesive of the present invention, when the component (A1) contains a styrenic block copolymer having a styrene content of 20 to 50% by weight and a diblock copolymer content of 20 to 80% by weight Since a large amount of the diblock copolymer is contained, the adhesion is further improved, and the adhesion between the substrate and the adhesive is further improved to make it difficult to form a gap between the two. Therefore, water is less likely to enter between the straw package and the container, and the water-resistant adhesion of the hot melt adhesive is improved.

  When the thermoplastic block copolymer (A) further includes the component (A2): triblock styrenic block copolymer, the cohesion of the hot melt adhesive is further improved, and the hot melt adhesive has a tack and a cohesion. It excels in balance with power. Therefore, when the straw package is peeled from the container, the hot melt adhesive is less likely to be cohesively broken, and as a result, the interfacial failure is more likely to occur, and the straw package can be peeled more beautifully from the container.

  When the hot melt adhesive further includes (B) tackifier resin, (C) softener and (D) wax, the adhesive is excellent in balance between cohesion and tack, and the straw package is attached easily to the substrate The coating properties to the substrate can be improved, the adhesion at low temperature can also be improved, the solidification speed after coating can be faster, and the initial cohesion can be further improved. The application of the straw package to the container is quicker, and the straw package becomes more difficult to separate from the container immediately after application.

A container with a straw (paper pack) is schematically shown in a perspective view. The container with a straw (plastic cup) is schematically shown in a front view.

The hot melt adhesive of the present invention has (A) a thermoplastic block copolymer based on a vinyl aromatic hydrocarbon and a conjugated diene compound (hereinafter also referred to as "(A) thermoplastic block copolymer").
In the present invention, “(A) thermoplastic block copolymer” is a block copolymer of a vinyl aromatic hydrocarbon and a conjugated diene compound, and is usually a block based on a vinyl aromatic hydrocarbon It is a resin composition containing a block copolymer having a block based on a vinyl aromatic hydrocarbon block ") and a conjugated diene compound (hereinafter also referred to as a" conjugated diene compound block ").

  The “vinyl aromatic hydrocarbon” means an aromatic hydrocarbon compound having a vinyl group, and specifically, for example, styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1 And 3-dimethylstyrene, α-methylstyrene, vinyl naphthalene, vinyl anthracene and the like. Styrene is particularly preferred as the vinyl aromatic hydrocarbon. These vinyl aromatic hydrocarbons can be used alone or in combination.

The "conjugated diene compound" means a diolefin compound having at least one pair of conjugated double bonds. As the "conjugated diene compound", specifically, for example, 1,3-butadiene, 2-methyl-1,3-butadiene (or isoprene), 2,3-dimethyl-1,3-butadiene, 1,3- Pentadiene and 1,3-hexadiene can be exemplified. As the conjugated diene compound, 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 a non-hydrogenated product or a hydrogenated product.

  Specifically, the "non-hydrogenated additive" of the "(A) thermoplastic block copolymer" can be exemplified as it is a block copolymer in which the block based on the conjugated diene compound is not hydrogenated. Further, the “hydrogenated substance” of “(A) thermoplastic block copolymer” specifically refers to a block copolymer in which all or a part of the block based on a conjugated diene compound is hydrogenated. it can.

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

  Specific examples of the “non-hydrogenated additive” of the thermoplastic block copolymer (A) include block copolymers of styrene and isoprene, and block copolymers of styrene and butadiene. (A) As the "hydrogenated substance" of the thermoplastic block copolymer, specifically, for example, a block copolymer of hydrogenated styrene and isoprene and a block copolymer of hydrogenated styrene and butadiene are exemplified. it can.

  In the hot melt adhesive according to the present invention, the thermoplastic block copolymer (A) comprises a component (A1): a styrenic block copolymer containing a diblock copolymer (hereinafter, also simply referred to as “diblock”). Including union.

  In the present invention, the (A1) styrenic block copolymer has a styrene content of 20 to 50% by weight, a diblock content of 20 to 80% by weight, and a viscosity of 100% to 25% by weight of a 25% by weight toluene solution at 25 ° C. The viscosity is preferably 3500 mPa · s or less.

In the present specification, the "styrene content" refers to the proportion of styrene blocks contained in a styrenic block copolymer. The styrene content of (A1) is preferably 20 to 50% by weight, and more preferably 30 to 50% by weight.
In the hot melt adhesive of the present invention, when the styrene content of the component (A1) is in the above range, the cohesion is improved, and adhesion to normal temperature and low temperature (about 5 ° C.) to paper, plastic and metal Is more excellent.

In the present invention, "diblock" means a block copolymer having two blocks, but usually "vinyl-based aromatic block", preferably "styrene block" and "conjugated diene compound block" or hydrogen It means a block copolymer having one “conjugated diene compound block” added, for example, and can be represented by the following chemical formula (1).
S-E (1)
Here, in the chemical formula (1), S is a vinyl-based aromatic block, preferably a styrene block, and E is a conjugated diene compound block or a hydrogenated "conjugated diene compound block". The conjugated diene compound is preferably butadiene or isoprene.

  Therefore, the "diblock content" refers to the proportion of "diblock copolymer" contained in the styrenic block copolymer. The diblock content of the component (A1) is preferably 20 to 80% by weight, and more preferably 50 to 80% by weight.

  When the diblock content of the component (A1) is in the above range, the hot melt adhesive of the present invention maintains adhesion to paper, plastic and metal at normal temperature and low temperature (around 5 ° C.) Furthermore, it is also excellent in water-resistant adhesion.

  In the present invention, "the viscosity at 25 ° C of a 25 wt% toluene solution" refers to the viscosity at 25 ° C of a 25 wt% concentration solution using toluene as a solvent, and may be measured using various viscometers. Although it can be measured, for example, it is measured using a Brookfield BM viscometer (spindle No. 2).

  The viscosity at 25 ° C of the 25 wt% toluene solution of the component (A1) is preferably 100 to 3500 mPa · s, more preferably 100 to 1000 mPa · s, and more preferably 100 to 500 mPa · s Is most preferred.

  The hot melt adhesive of the present invention is excellent in low temperature coating when the viscosity at 25 ° C. of a 25 wt% toluene solution of the component (A1) is in the above range, and uniform coating on a substrate becomes possible. As a result, the adhesiveness at low temperature (around 5 ° C.) is more excellent.

In the present invention, commercially available block copolymers can be used as the component (A1). For example, Asaprene T432 (trade name), Asaprene T438 (trade name), manufactured by Asahi Kasei Chemicals Corporation, Asaprene T439 (trade name), and Quintac 3270 (trade name) manufactured by Nippon Zeon Co., Ltd. can be exemplified.
The component (A1) can contain a triblock copolymer and the like in addition to the diblock copolymer.

  In the present invention, it is preferable that the (A) thermoplastic block copolymer further contains (A2) a triblock styrene-based block copolymer in addition to the component (A1).

  The diblock content of the triblock styrenic block copolymer is 0% by weight. That is, the (A2) triblock styrenic block copolymer can be clearly distinguished from the aforementioned (A1) component.

  In the present invention, the styrene content of the (A2) triblock styrenic block copolymer is preferably 25 to 50% by weight, and particularly preferably 35 to 50% by weight. When the styrene content of (A2) is in the above range, the cohesion of the hot melt adhesive is improved, and the adhesion is further improved.

Examples of the triblock styrene block copolymer (A2) include styrene-butadiene-styrene copolymer (hereinafter also referred to as “SBS”) and styrene-isoprene-styrene copolymer (hereinafter also referred to as “SIS”). can do.
Furthermore, the triblock styrene-based block copolymer (A2) may be a hydrogen additive. The hydrogen additive is as already described. As such a hydrogenated substance, for example, hydrogenated styrene-isoprene-styrene copolymer (hereinafter also referred to as "SEPS") and hydrogenated styrene-butadiene-styrene copolymer (hereinafter also referred to as "SEBS") Can be illustrated.

  A commercial item can be used as a (A2) triblock styrene type block copolymer. For example, TR2000 (trade name), TR 2003 (trade name) and TR 2250 (trade name) manufactured by JSR Corporation; Tufprene 125, Tufprene A and Asaprene T 420 (trade name) manufactured by Asahi Kasei Chemicals Corporation; and Dexco (trade name) Examples include Vector4411A (trade name) and Vector 4211A (trade name) manufactured by Co., Ltd.

  When the hot melt adhesive of the present invention contains (A2), the cohesion is further improved, and the balance between the tack and the cohesion is more excellent. Therefore, when the straw package is peeled from the container, the hot melt adhesive is less likely to be cohesively broken, and as a result, the interfacial failure is more likely to occur, and the straw package can be peeled more beautifully from the container.

Furthermore, the present invention is a hot melt adhesive comprising a thermoplastic block copolymer based on (A) vinyl aromatic hydrocarbon and a conjugated diene compound,
(A) The thermoplastic block copolymer provides a hot melt adhesive for containers with a straw, which comprises a diblock styrenic block copolymer.
(A) Since the thermoplastic block copolymer contains a diblock styrenic block copolymer, it has excellent adhesion to paper and polyolefin substrates, and also to adhesion at low temperatures (around 5 ° C.) Excellent, suitable for making containers with straws.

  The hot melt adhesive of the present invention preferably comprises (B) a tackifying resin, (C) a softener and (D) a wax.

  The tackifying resin (B) is not particularly limited as long as it is one that is usually used for a hot melt adhesive and that a hot melt adhesive intended by the present invention can be obtained. When the hot melt adhesive of the present invention has (B) a tackifying resin, it is more excellent in the balance between the adhesive cohesion and the tack. Therefore, the straw package can be easily attached to a substrate such as paper or plastic via the hot melt adhesive of the present invention.

  As such (B) tackifying resin, for example, natural rosin, modified rosin, hydrogenated rosin, glycerol ester of natural rosin, glycerol ester of modified rosin, pentaerythritol ester of natural rosin, pentaerythritol ester of modified rosin, water Pentaerythritol ester of added rosin, copolymer of natural terpene, three-dimensional polymer of natural terpene, hydrogenated derivative of copolymer of hydrogenated terpene, polyterpene resin, hydrogenated derivative of phenolic modified terpene resin, aliphatic petroleum hydrocarbon resin, fatty Of hydrogenated petroleum hydrocarbon resin, aromatic petroleum hydrocarbon resin, hydrogenated derivative of aromatic petroleum hydrocarbon resin, cyclic aliphatic petroleum hydrocarbon resin, hydrogenated derivative of cyclic aliphatic petroleum hydrocarbon resin be able to.

  These tackifying resins can be used alone or in combination. As the tackifying resin, a liquid type tackifying resin can also be used as long as the color tone is colorless to pale yellow and the odor is not substantially present and the heat stability is good. When these properties are comprehensively considered, hydrogenated derivatives such as resins are preferable as tackifying resins. In addition, you may use together non-hydrogenated tackifying resin.

  (B) A commercial item can be used as tackifying resin. As such commercial products, for example, ECR 179 EX (trade name) manufactured by Tonex Co., Ltd .; Maruka Clearer H (trade name) manufactured by Maruzen Petrochemical Co., Ltd .; Alcon M 100 (trade name) manufactured by Arakawa Chemical Co., Ltd .; Imarb manufactured by Idemitsu Kosan Co., Ltd. S100 (trade name); Clearron K100 (trade name) manufactured by Yashara Chemical Co., Ltd., Clearon K 4090 (trade name) and Clearon K4100; ECR 179 EX (trade name) manufactured by Tonex Co., Ltd. and ECR 231 C (trade name), RIGALITE manufactured by Eastman Chemical Co., Ltd. C6100L (trade name) and Rigalite C8010 (trade name); FTR 2140 (trade name) manufactured by Mitsui Chemicals, Inc. can be exemplified. In addition, Quinton DX390N and Quinton DX395 manufactured by Nippon Zeon Co., Ltd. can be exemplified as non-hydrogenated tackifying resins. Also, these commercially available tackifying resins can be used alone or in combination.

  The softener (C) is blended for the purpose of lowering the melt viscosity of the hot melt adhesive, imparting flexibility, and improving the wettability to the adherend. The softener (C) is not particularly limited as long as it is compatible with the block copolymer and the hot melt adhesive intended by the present invention can be obtained. When the hot melt adhesive of the present invention has (C) a softener, the coating property to a substrate such as paper or plastic is improved, and as a result, the adhesiveness at low temperature (especially around 5 ° C.) is also It can improve.

  Examples of the softener (C) include paraffinic oils, naphthenic oils and aromatic oils. Among these, when the component (C) contains at least one of paraffinic oil and naphthenic oil, the compatibility between the component (A) and the component (B) is further enhanced, and the components become difficult to separate. The adhesive strength of the hot melt adhesive can also be further improved by mixing the components more uniformly without separation.

  A commercial item can be used as a softener (C). For example, White Oil Broom 350 (trade name) manufactured by Kukdong Oil & Chem, Diana Flecia S32 (trade name) manufactured by Idemitsu Kosan Co., Ltd., Diana Process Oil PW-90 (trade name), DN Oil KP-68 (trade name), BP Chemicals Enerper M 1930 (trade name), Crompton Kaydol (trade name), Esso Primol 352 (trade name), Idemitsu Kosan Co. Process Oil NS 100, Petro China Company KN 4010 (trade name) Sun Pure N90 manufactured by Nippon San Oil Co., Ltd. can be exemplified. These (C) softeners can be used alone or in combination.

  In the present specification, the (D) wax is an organic substance that is solid at normal temperature and becomes a liquid when heated, and is generally referred to as a “wax”, as long as it has a wax-like property, There is no particular limitation as long as the hot melt adhesive according to the present invention can be obtained. The weight average molecular weight of the wax is generally less than 10,000.

When the hot melt adhesive of the present invention contains (D) a wax, the solidification speed after coating becomes faster, and the initial cohesion can be further improved. Therefore, the application of the straw package to the container becomes quicker, and the straw package becomes more difficult to peel off from the container immediately after the application.
(D) Wax is a wax generally used for hot melt adhesives, and may be modified with a polar functional group or the like as long as the hot melt adhesive intended by the present invention can be obtained. Good.

  Specifically, synthetic wax-based compounds such as Fischer-Tropsch wax and polyolefin wax (polyethylene wax and polypropylene wax); petroleum waxes such as paraffin wax and microcrystalline wax; natural waxes such as castor wax;

  In the present invention, the (D) wax preferably includes a Fischer-Tropsch wax. The Fischer-Tropsch wax refers to one which is synthesized by the Fischer-Tropsch method and generally referred to as a Fischer-Tropsch wax (including an acid-modified product). The Fischer-Tropsch wax is obtained by fractionating a wax from which a component molecule has a relatively wide carbon number distribution such that the component molecule has a narrow carbon number distribution. When the wax (D) contains a Fischer-Tropsch wax, the balance between the solidification speed and the initial cohesion after application of the hot melt adhesive can be further improved.

  As typical Fischer Tropsch wax, Sazole H1 (trade name), Sazole H8 (trade name), Sazole H 105 (trade name) and Sazole C 80 (trade name) can be exemplified, and all of them are commercially available from Sazol Wax Co., Ltd. It is done.

  Moreover, as a commercial item of paraffin wax, Paraffin Wax-150 by Nippon Seiwa Co., Ltd. is mentioned. The wax (D) may be used alone or in combination of two or more.

The hot melt adhesive of the present invention preferably contains (E) a stabilizer (hereinafter sometimes referred to as "component (E)") in addition to the components (A) to (D).
"Stabilizer" is a compound formulated to improve the stability of the hot melt adhesive by preventing molecular weight reduction, gelation, coloring, generation of odor, etc. of the hot melt adhesive due to heat. It is not particularly limited as long as the hot melt adhesive intended by the present invention can be obtained. As a "stabilizer", an antioxidant and a ultraviolet absorber can be illustrated, for example.

  "UV absorbers" are used to improve the light fastness of hot melt adhesives. An "antioxidant" is used to prevent oxidative degradation of the hot melt adhesive. The antioxidant and the ultraviolet light absorber can be used as long as they can obtain the intended paper product to be described later, and are not particularly limited.

  As an antioxidant, a phenol type antioxidant, a sulfur type antioxidant, and a phosphorus type antioxidant can be illustrated, for example. As an ultraviolet absorber, a benzotriazole type ultraviolet absorber and a benzophenone series ultraviolet absorber can be illustrated, for example. Furthermore, lactone stabilizers can also be added. These can be used alone or in combination. The following products can be used as commercial products of antioxidants.

  Specifically, SUMILYMER GM (trade name) manufactured by Sumitomo Chemical Co., Ltd., SMILIZER TPD (trade name) and SUMILIZER TPS (trade name), IRGANOX 1010 (trade name) manufactured by BASF Japan Ltd., IRGANOX HP2225FF (Trade name), Irgafos 168 (trade name) and Irganox 1520 (trade name), Tinuvin P, JF 77 (trade name) manufactured by Johoku Chemical Co., Ltd., Tominox TT (trade name) manufactured by AP Corporation, manufactured by Adeka AO-412S (trade name) can be exemplified. These stabilizers can be used alone or in combination.

  The hot melt adhesive of the present invention may further comprise a particulate filler. The particulate filler may be one generally used, and is not particularly limited as long as the hot melt adhesive intended 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 spherical) are not particularly limited.

  The hot melt adhesive according to the present invention can be produced by any of (A) component, (B) component, (C) component and (D) component, using a generally known method for producing a hot melt adhesive. Accordingly, it can be produced by blending (E) a stabilizer and various additives. For example, it can be manufactured by blending a predetermined amount of the above-mentioned components and heating and melting. The order of adding each component, the heating method, and the like are not particularly limited as long as the target hot melt adhesive can be obtained.

As an embodiment of the present invention, the blending ratio of each component is preferably as follows.
In the hot melt adhesive of the present invention, the component (A) is preferably blended in an amount of 10 to 40 parts by weight, based on 100 parts by weight of the components (A) to (D), and 10 to 30 parts by weight. It is more preferable to be partially blended. The component (A1) is preferably blended in an amount of 3 to 30 parts by weight, and more preferably 3 to 25 parts by weight, based on 100 parts by weight of the components (A) to (D). When the hot melt adhesive of the present invention contains the component (A1) in the above range, the hot melt adhesive is excellent in the balance of adhesion to substrates such as paper, plastic, and metal.

The component (B) is preferably blended in an amount of 30 to 70 parts by weight, and more preferably 40 to 60 parts by weight, based on 100 parts by weight of the components (A) to (D).
Component (C) is preferably blended in an amount of 10 to 50 parts by weight, more preferably 20 to 40 parts by weight, based on 100 parts by weight of components (A) to (D). Most preferably, it is blended in an amount of 20 to 30 parts by weight.

  Component (D) is preferably blended in an amount of 1 to 40 parts by weight, and more preferably 5 to 25 parts by weight, based on 100 parts by weight of the total amount of components (A) to (D). It is most preferable that 5 to 20 parts by weight be blended.

  When the component (E) is added to the hot melt adhesive of the present invention, the component (E) is added in an amount of 0.1 to 1 part by weight based on 100 parts by weight of the total of the components (A) to (D). It is preferable to be added, more preferably 0.1 to 0.5 parts by weight.

  As a further preferred embodiment of the present invention, the viscosity (or melt viscosity) at 160 ° C. of the hot melt adhesive is preferably 6000 mPa · s or less, particularly preferably 5000 mPa · s or less, and 1000 to 2000 mPa · s. It is most preferable that

  The hot melt adhesive can be more easily and uniformly coated when the viscosity at 160 ° C. is in the above range, and the adhesion between the straw package and the container is further improved. The viscosity (or melt viscosity) at 160 ° C. in the present specification means a value measured with a Brookfield viscometer using a No. 27 rotor.

  The softening point of the hot melt adhesive according to the present invention is preferably 70 to 130 ° C, more preferably 80 to 120 ° C, and particularly preferably 80 to 110 ° C. When the softening point is in the above range, the balance between the solidification speed of the hot melt adhesive and the initial cohesion is further improved. The softening point was measured according to the ring & ball method.

  The hot melt adhesive of the present invention can take various shapes, but is generally block-like at normal temperature. The block-like hot melt adhesive is obtained by cooling and solidifying the product obtained by the above-mentioned production method as it is.

  The hot melt adhesive of the present invention can be used by coating on an adherend. At the time of coating, since it is not necessary to mix an organic solvent into the hot melt adhesive, it is environmentally preferable.

  The coating method can use the application (or coating) method of the generally well-known hot-melt adhesive agent, and it is divided roughly into contact coating and non-contact coating. "Contact coating" refers to a coating method that brings a jet machine into contact with a member or film when coating a hot melt adhesive, and "non-contact coating" coats a hot melt adhesive. In this case, it refers to a coating method in which the sprayer is not in contact with the member or film. As a contact coating method, for example, slot coater coating, roll coater coating and the like can be exemplified, and as a non-contact coating method, for example, spiral coating which can be applied in a spiral, omega coating which can be applied in a wavelike manner Examples include control seam coating, slot spray coating and curtain spray coating capable of surface coating, dot coating capable of dot coating, and bead coating capable of linear coating.

Since the hot melt adhesive of the present invention is used to produce a container with a straw, the coating method is most preferably dot coating which can be applied in a dot-like manner.
A hot melt adhesive is dot-coated on the straw package or container side at 120 to 180 ° C., and the straw package is attached to the container via the hot melt adhesive, and a container with a straw can be preferably obtained.

  FIG. 1 is a perspective view schematically showing a paper pack which is an embodiment of a container with a straw according to the present invention. As shown in the figure, a straw puncturing hole 3 is formed on the top surface 2 of the container 1 with a straw. A straw package 6 is held by a hot melt adhesive (not shown) on the side of the container 1 with a straw. The straw package 6 contains the straw 5 with a film of polyolefin or the like.

  FIG. 2 schematically shows in a front view a plastic cup which is another embodiment of the container with a straw according to the present invention. As shown in the figure, in the container 1 with a straw, a straw package 6 containing a straw 5 is attached to the side surface of the container (plastic base material) with a hot melt adhesive (not shown). Examples of plastic substrates include polypropylene and polyethylene.

  The container with a straw is not limited to the embodiment of FIGS. 1 and 2. For example, the container may be a metal can (such as an aluminum can and a steel can) made of metal, and furthermore, a straw may be directly attached to the container without using a straw package.

EXAMPLES The present invention will be specifically and specifically described below by Examples and Comparative Examples. However, these Examples are only one aspect of the present invention, and the present invention is not limited by these examples.
In the description of the examples, unless otherwise stated, parts not considering the solvent are based on parts by weight and% by weight.

The components used in this example are shown below.
(A) Thermoplastic block copolymer
(A1) Diblock-Containing Styrene-Based Block Copolymer (A1-1) SBS (Asaprene T432 (trade name), manufactured by Asahi Kasei Chemicals Corporation, styrene content 30% by weight, diblock content 25% by weight)
(A1-2) SBS (Asaprene T 438 (trade name), manufactured by Asahi Kasei Chemicals Corporation, styrene content 35% by weight, diblock content 70% by weight)
(A1-3) SBS (Asaprene T439 (trade name), manufactured by Asahi Kasei Chemicals, 45% by weight of styrene content, 62% by weight of diblock content)
(A1-4) SIS (Quintac 3270 (trade name), manufactured by Nippon Zeon Co., Ltd., styrene content 24% by weight, diblock content 67% by weight)
(A1-5) SEBS (Kraton G1726 (trade name), manufactured by Kraton Polymers, styrene content 30% by weight, diblock content 70% by weight)

(A2) Triblock styrenic block copolymer
(A2-1) SBS (Tafprene 125 (trade name), manufactured by Asahi Kasei Chemicals Corporation, styrene content 40% by weight)
(A2-2) SBS (Tafprene A (trade name), manufactured by Asahi Kasei Chemicals Corporation, styrene content 40% by weight)
(A2-3) SBS (TR 2250 (trade name), manufactured by JSR, 52% by weight of styrene content)

(B) Tackifying resin
(B-1) Hydrogenated tackifying resin (Alcon M100 (trade name), manufactured by Arakawa Chemical Industries, Ltd.)
(B-2) Hydrogenated tackifying resin (Aimerb S100 (trade name), manufactured by Idemitsu Kosan Co., Ltd.)
(B-3) Rosin ester-type tackifying resin (SYLVALITE RE105L (trade name), manufactured by Arizona Chemical Co., Ltd.)

(C) Softener
(C-1) Paraffin oil (Daphne oil KP 68 (trade name), manufactured by Idemitsu Kosan Co., Ltd.)
(C-2) Paraffin oil (Diana Process Oil S32 (trade name), manufactured by Idemitsu Kosan Co., Ltd.)
(C-3) naphthenic oil (Sun Pure N90 (trade name), manufactured by Nippon San Oil Co., Ltd.)

(D) Wax
(D-1) Fischer Tropsch wax (Sazole H1 (trade name), manufactured by Sazole Company)
(D-2) Paraffin wax (Paraffin Wax-150 (trade name), manufactured by Nippon Seiwa Co., Ltd.)
(D-3) Microcrystalline wax (Microwax 180 (trade name), manufactured by JX Nippon Oil & Energy Corporation)
(E) Stabilizer
(E-1) Antioxidant (Adekastab AO-412S (trade name), manufactured by Adeka Corporation)

Each component of (A) to (E) is heated, melted and mixed at about 145 ° C. for about 1.5 hours in proportions (parts by weight) shown in Tables 1 to 3 using a universal stirrer, Examples and Comparative Examples Hot melt adhesives were produced.
The melt viscosity, softening point, adhesion performance to paper packs and plastic cups, and water-resistant adhesion performance using paper packs were evaluated for the above-described hot melt adhesives.
The sample preparation method for evaluation, the evaluation test method, and the evaluation criteria are described below.

<Viscosity measurement>
The hot melt adhesive was melted at each temperature of 120 ° C., 140 ° C., 160 ° C. and 180 ° C., and after 20 minutes, the viscosity was measured using a # 27 rotor using a Brookfield viscometer.
<Softening point measurement>
The softening point of the hot melt adhesive was measured using the ring and ball method (the method described in Japan Adhesive Industry Association Standard JAI-7-1999).

<Adhesive strength evaluation>
(Sample preparation)
On a paper pack or plastic cup which is an adherend (or base material), 0.03 to 0.04 g of a hot melt adhesive was applied using a hot melt gun. The coating temperature was 180 ° C. The adherend to which the hot melt adhesive had been applied and the straw package were superposed and pressed with a finger to obtain a sample for evaluation.
The sample for adhesive strength evaluation at normal temperature and low temperature was used for evaluation after standing at room temperature (23 ° C.) for 24 hours.
The sample for evaluation of water-resistant adhesive strength was prepared from the sample of the paper pack prepared in the above-mentioned adhesive strength evaluation test at normal temperature and low temperature. The sample of the adherend-packed paper was immersed in tap water at room temperature for another 12 hours. Before the test, water was wiped from the paper pack with a paper towel to obtain a sample for water resistance adhesive strength evaluation.

(Test method)
Using a universal tensile tester (manufactured by Shimadzu Corporation), the peeling test was performed on the sample for adhesive strength evaluation prepared above at a speed of 300 mm / min. For each of the hot melt adhesives (Examples and Comparative Examples), at least three samples are measured to obtain the value of each adhesive strength, and their average value is calculated to obtain the value of the average adhesive strength (simply (Also referred to as “strength”). The temperature was measured at 5 ° C. and 23 ° C., respectively.
Furthermore, for each sample, the peeled portion was visually observed to examine its state.
The evaluation criteria of adhesive strength evaluation are shown below.

Adhesive strength evaluation A (Excellent): Average adhesive strength is 15 N or more B (Good): Average adhesive strength is 8 N or more to less than 15 N C (Not good): Average adhesive strength is less than 8 N

State of peeled part (displayed to the right of A to C in adhesion strength evaluation)
++: Interface failure (the surface of the substrate is broken)
+: Composite fracture in which interfacial fracture and cohesive fracture are mixed (fracture of both the surface of the substrate and the adhesive are mixed)
*: Cohesive failure (adhesive was broken)
The adhesive strength is preferably higher (B is more than A and C is more than A), but for A and B, interface failure is more preferable than cohesive failure.

  As shown in Tables 1 and 2, the hot melt adhesives of Examples 1 to 12 contain a styrenic block copolymer containing component (A1): diblock, and therefore, at low temperature (5 ° C.) and at normal temperature (5 ° C.) It is excellent in the adhesive strength (to a paper pack and a plastic cup) at the time of 23 ° C, and also excellent in water resistant adhesive strength. The hot melt adhesive of the example is suitable for a container with a straw since it is excellent in the balance of the above-mentioned performance.

As shown in Table 3, the hot melt adhesive of Comparative Examples 1 to 4 has a low temperature (5 ° C.) with any of the adherends (or base materials) as compared with the adhesives of Examples 1 to 12. And the adhesive strength at normal temperature (23 ° C) is poor. The water resistant adhesive strength of the hot melt adhesive of the comparative example is significantly inferior to that of the example. The hot melt adhesive of the comparative example can not be used substantially for a container with a straw because the water-resistant adhesive strength is C.
Accordingly, since the hot melt adhesive contains a diblock styrenic block copolymer, it has been shown to be suitable as a hot melt adhesive for producing a container with a straw.

  The present invention provides a hot melt adhesive for a container with a straw, a straw package obtained by applying the hot melt adhesive, and a container with a straw. The hot melt adhesive according to the present invention is excellent in adhesion to paper packs and plastic cups at normal temperature and low temperature, and further excellent in water-resistant adhesion, so that containers with straws, in particular, paper pack containers are manufactured. It is suitable.

1 container with straw 2 side 3 straw hole 5 straw 6 straw package

Claims (3)

A hot melt adhesive comprising (A) a thermoplastic block copolymer based on a vinyl aromatic hydrocarbon and a conjugated diene compound , (B) a tackifying resin, (C) a softener and (D) a wax ,
(A) a thermoplastic block copolymer, (A1) component: styrene-based block copolymer containing diblock copolymer and the component (A2): see contains a triblock styrenic block copolymer,
The hot melt adhesive for containers with a straw which contains 3-30 weight part of (A1) components with respect to 100 weight parts of total weight of (A) component-(D) component .   The hot melt adhesive according to claim 1, wherein the component (A1) comprises a styrenic block copolymer having a styrene content of 20 to 50% by weight and a diblock copolymer content of 20 to 80% by weight. Agent. A container with a straw, wherein the straw is held in the container by the hot melt adhesive according to claim 1 or 2 .

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