JP2019026849A - Hot melt adhesive for container with straw - Google Patents

Abstract

To provide a hot melt adhesive which is excellent in adhesive properties to a substrate such as paper and polyolefin or the like, excellent in adhesive properties during low temperature, suitable for adhering a straw package to a container formed of the substrate, and in addition, handling of the container with straw during summer is also considered and excellent also in waterproof adhesive properties.SOLUTION: A hot melt adhesive comprises (A) a thermoplastic block copolymer based on vinyl aromatic hydrocarbon and conjugated diene compound. (A) The thermoplastic block copolymer includes (A1) a styrenic block copolymer including a diblock copolymer. The hot melt adhesive is excellent in adhesive properties to a substrate such as paper and polyolefin, excellent in adhesive properties during low temperature, suitable for adhering a straw package to a container formed of the substrate and excellent also in waterproof adhesive properties, so that, it can be preferably used as the hot melt adhesive for a container with straw.SELECTED DRAWING: None

Description

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

  A container with a straw refers to a container to which a straw packaging body obtained by housing a suction straw in a plastic packaging bag is attached. Containers are generally often filled with beverages. Straw containers are roughly categorized by the material used to manufacture the containers. A paper pack if the container is made of paper, a (metal) can if the container is made of metal (more specifically, an aluminum can if made of aluminum, a steel can if made of steel, etc.), and a container such as polypropylene If it is made of plastic such as polyethylene terephthalate, it is called a plastic cup.

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

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

Patent document 2 describes fixing a straw packaging body to a container using a hot-melt-adhesive (refer patent document 2 [0010] etc.).
However, in Patent Document 2, the composition of the hot melt adhesive used is completely unknown.

  Hot melt adhesive for containers with straws must have excellent adhesion to plastic films, such as polyolefin, for packaging straws, and substrates used to make containers, such as paper and plastic substrates . Furthermore, considering that the container to be manufactured is refrigerated, the hot melt adhesive must be excellent in adhesiveness at a low temperature (around 5 ° C.). Furthermore, in the summer, the hot melt adhesive is also required to have excellent water-resistant adhesion because the container is condensed or the container with a straw is immersed in cold water.

  As described above, the hot melt adhesive for containers with a straw is required to have various performances suitable for beverage container applications, but no hot melt adhesive that completely satisfies the demands of consumers has been found.

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

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

  As a result of extensive research, the present inventor has surprisingly found that a hot-melt adhesive containing a diblock type styrenic block copolymer can solve the above-mentioned problems, and has completed the present invention. I came to let you.

The present invention, in one aspect,
(A) A hot melt adhesive comprising a thermoplastic block copolymer based on a vinyl aromatic hydrocarbon and a conjugated diene compound,
(A) A thermoplastic block copolymer provides a hot-melt adhesive for a container with a straw, which includes a styrene-based block copolymer containing (A1) component: diblock copolymer.

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

In yet another aspect of the present invention, there is provided a hot melt adhesive, wherein (D) the wax comprises a Fischer-Tropsch wax.
Furthermore, the preferable aspect of this invention provides the hot-melt-adhesive which contains 3-30 weight part of (A1) with respect to 100 weight part of total weight of (A)-(D).
The present invention preferably provides a straw package that is attached to a container with the hot melt adhesive described above and encloses a straw, or a container with a straw, in which the straw is held in the container with the hot melt adhesive described above. be able to.

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

  In the hot melt adhesive of the present invention, the component (A1) contains a styrene 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, the adhesion between the base material and the adhesive is further improved, and it becomes difficult to form a gap between the two. Accordingly, water hardly enters between the straw wrapping body and the container, so that the water-resistant adhesive property of the hot melt adhesive is improved.

  When the (A) thermoplastic block copolymer further contains the component (A2): the triblock styrene block copolymer, the cohesive force of the hot melt adhesive is further improved, and the hot melt adhesive is tacky and cohesive. Excellent balance with power. Therefore, when the straw package is peeled off from the container, the hot melt adhesive is less likely to cohesively break, and as a result, interface breakage is more likely to occur, and the straw package can be peeled off more beautifully from the container.

  When the hot melt adhesive further contains (B) a tackifier resin, (C) a softener and (D) a wax, it is excellent in the balance between the cohesive force and tack of the adhesive, and easily attaches the straw package to the substrate. It can be applied, the coating property to the base material can be improved, the adhesiveness at low temperature can be improved, the solidification speed after coating becomes faster, and the initial cohesive force can also be improved. Application of the straw package to the container becomes quicker, and the straw package is more easily peeled off from the container immediately after application.

A container with straw (paper pack) is typically shown in a perspective view. A container with a straw (plastic cup) is typically 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) 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 (hereinafter “ It is a resin composition comprising a block copolymer having a block based on a conjugated diene compound (hereinafter also referred to as “conjugated diene compound block”) and a vinyl aromatic hydrocarbon block ”.

  The “vinyl aromatic hydrocarbon” means an aromatic hydrocarbon compound having a vinyl group, and specifically includes, for example, styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1 , 3-dimethylstyrene, α-methylstyrene, vinylnaphthalene, vinylanthracene and the like. Styrene is particularly preferable 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 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. As the conjugated diene compound, 1,3-butadiene and 2-methyl-1,3-butadiene are particularly preferable. 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 the “unhydrogenated product” of “(A) thermoplastic block copolymer” include a block copolymer as it is without a hydrogenated block based on a conjugated diene compound. The “hydrogenated product” of “(A) 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. it can.

  (A) The hydrogenated ratio of the “hydrogenated product” of the thermoplastic block copolymer can be represented by “hydrogenation rate”. (A) The “hydrogenation rate” of the “hydrogenated product” of the 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.

  (A) Specific examples of the “unhydrogenated product” of the thermoplastic block copolymer include a block copolymer of styrene and isoprene and a block copolymer of styrene and butadiene. (A) Specific examples of the “hydrogenated product” of the thermoplastic block copolymer include a hydrogenated styrene / isoprene block copolymer and a hydrogenated styrene / butadiene block copolymer. it can.

  In the hot melt adhesive according to the present invention, (A) the thermoplastic block copolymer is a styrene block copolymer containing (A1) component: diblock copolymer (hereinafter also simply referred to as “diblock”). Includes coalescence.

  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 a 25% by weight toluene solution at 25 ° C. of 100 to 100%. It is preferably 3500 mPa · s or less.

In the present specification, “styrene content” refers to the proportion of styrene blocks contained in the styrenic block copolymer. (A1) preferably has a styrene content of 20 to 50% by weight, more preferably 30 to 50% by weight.
When the styrene content of the component (A1) is in the above range, the hot melt adhesive of the present invention has improved cohesive force and adheres to paper, plastic, and metal at normal temperature and low temperature (around 5 ° C.). More excellent.

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

  Accordingly, “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 adhesiveness at normal temperature and low temperature (around 5 ° C.) to paper, plastic, and metal, Furthermore, it is excellent in water-resistant adhesiveness.

  In the present invention, “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 can be measured using various viscometers. 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 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.

  When the viscosity at 25 ° C. of a 25 wt% toluene solution of the component (A1) is in the above range, the hot melt adhesive of the present invention is excellent in low temperature coating and can be applied uniformly to a substrate. Therefore, as a result, the adhesiveness at a low temperature (around 5 ° C.) is more excellent.

In the present invention, a commercially available block copolymer can be used as the component (A1). For example, Asaprene T432 (trade name), Asaprene T438 (trade name), Asaprene T439 (trade name) manufactured by Asahi Kasei Chemicals Co., Ltd.
In addition, (A1) component can contain a triblock copolymer etc. other than a diblock copolymer.

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

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

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

(A2) Examples of the triblock styrene block copolymer include styrene-butadiene-styrene copolymer (hereinafter also referred to as “SBS”) and styrene-isoprene-styrene copolymer (hereinafter also referred to as “SIS”). can do.
Further, the (A2) triblock styrene block copolymer may be a hydrogenated product. The hydrogenated product has already been described. Examples of such a hydrogenated product include a hydrogenated styrene-isoprene-styrene copolymer (hereinafter also referred to as “SEPS”) and a hydrogenated styrene-butadiene-styrene copolymer (hereinafter also referred to as “SEBS”). ).

  (A2) A commercially available product can be used as the triblock styrene block copolymer. For example, TR2000 (trade name), TR2003 (trade name), and TR2250 (trade name) manufactured by JSR Corporation; Tuffprene 125, Tuffprene A and Asaprene T420 (trade name) manufactured by Asahi Kasei Chemicals Corporation; and Dexco ( For example, Vector4411A (trade name), Vector4211A (trade name), and the like manufactured by KK can be exemplified.

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

Furthermore, the present invention is a hot melt adhesive comprising (A) 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 a container with a straw, including a diblock styrene block copolymer.
(A) Since the thermoplastic block copolymer contains a diblock styrene block copolymer, it has excellent adhesion to paper and polyolefin substrates, and also exhibits adhesion at low temperatures (around 5 ° C). Excellent, suitable for making containers with straws.

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

  (B) 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. When the hot melt adhesive of the present invention has (B) a tackifying resin, the hot melt adhesive is excellent in the balance between the cohesive force and tack of the adhesive. 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.

  Examples of such (B) 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. An unhydrogenated tackifying resin may be used together.

  (B) A commercial item can be used as tackifying resin. Examples of such commercially available products include ECR179EX (trade name) manufactured by Tonex Co., Ltd .; Marcclear H (trade name) manufactured by Maruzen Petrochemical Co., Ltd .; Alcon M100 (trade name) manufactured by Arakawa Chemical Co., Ltd .; S100 (trade name); Clearon K100 (trade name), Clearon K4090 (trade name) and Clearon K4100 manufactured by Yashara Chemical Co .; ECR179EX (trade name) and ECR231C (trade name) manufactured by Tonex, Rigalite manufactured by Eastman Chemical Co., Ltd. Examples thereof include C6100L (trade name) and Rigalite C8010 (trade name); FTR 2140 (trade name) manufactured by Mitsui Chemicals. Further, examples of the non-hydrogenated tackifying resin include quinton DX390N and quinton DX395 manufactured by Nippon Zeon. These commercially available tackifying resins can be used alone or in combination.

  (C) A softening agent is mix | blended for the purpose of the melt viscosity fall of a hot-melt-adhesive, provision of a softness | flexibility, and the improvement to the to-be-adhered body. The (C) softener is not particularly limited as long as it is compatible with the block copolymer and can obtain the hot melt adhesive targeted by the present invention. When the hot melt adhesive of the present invention has (C) a softening agent, 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 improved. Can improve.

  (C) Examples of the softening agent include paraffinic oil, naphthenic oil, and aromatic oil. Among these, when the component (C) contains at least one of paraffinic oil and naphthenic oil, the compatibility of the component (A) and the component (B) is further increased, and the components are difficult to separate. The adhesive strength of the hot melt adhesive can be further improved by mixing the components more uniformly without being separated.

  (C) As a softener, a commercial item can be used. 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. Emerper M1930 (trade name) manufactured by Chemicals, Kaydol (trade name) manufactured by Crompton, Primol 352 (trade name) manufactured by Esso, Process Oil NS100 manufactured by Idemitsu Kosan Co., Ltd., and KN4010 manufactured by Petro China Company (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 this specification, the (D) wax is an organic substance that is solid at room temperature and becomes a liquid when heated, generally referred to as “wax”, and 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) wax, the solidification speed after coating becomes faster and the initial cohesive force can be further improved. Therefore, the straw package can be more quickly applied to the container, and the straw package can be more easily removed from the container immediately after being attached.
(D) The wax is a wax generally used for a hot melt adhesive, 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.

  Specific examples include 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 caster wax; and the like.

  In the present invention, the (D) wax preferably includes a Fischer-Tropsch wax. Fischer-Tropsch wax refers to those synthesized by the Fischer-Tropsch method and generally used as Fischer-Tropsch wax (including acid-modified products). Fischer-Tropsch wax is obtained by separating wax from component wax having a relatively wide carbon number distribution so that component molecules have a narrow carbon number distribution. (D) When a wax contains a Fischer-Tropsch wax, the balance of the solidification speed | rate after application | coating of a hot-melt-adhesive and initial stage cohesive force can improve more.

  Examples of typical Fischer-Tropsch waxes include Sazol H1 (trade name), Sazol H8 (trade name), Sazol H105 (trade name), and Sazol C80 (trade name), all of which are commercially available from Sazol Wax. Has been.

  Moreover, as a commercial product of paraffin wax, Paraffin Wax-150 manufactured by Nippon Seiwa Co., Ltd. may be mentioned. (D) A wax may be used individually by 1 type, and may be used in combination of 2 or more type.

The hot melt adhesive of the present invention preferably contains (E) a stabilizer (hereinafter also referred to as “(E) component”) in addition to the components (A) to (D).
“Stabilizer” means a compound that is added to improve the stability of hot melt adhesives by preventing the molecular weight reduction, gelation, coloring, generation of odors, etc. due to heat of the 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. The antioxidant and the ultraviolet absorber can be used as long as they can obtain the target paper product described later, and are not particularly limited.

  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. The following products can be used as commercial products of antioxidants.

  Specifically, 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 manufactured by BASF Japan Ltd. (Trade name), Irgafos 168 (trade name) and Irganox 1520 (trade name), Tinuvin P, JF77 (trade name) manufactured by Johoku Chemical Co., Ltd. Tominox TT (trade name) manufactured by API Corporation, manufactured by Adeka Corporation AO-412S (trade name) 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 generally 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 according to the present invention uses a generally known method for producing a hot-melt adhesive, and (A) component, (B) component, (C) component and (D) component, Accordingly, (E) a stabilizer and various additives can be blended and produced. For example, it can be manufactured by blending a predetermined amount of the above-mentioned components and heating and melting them. As long as the desired hot melt adhesive can be obtained, the order of adding the components, the heating method, and the like are not particularly limited.

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, and 10 to 30 parts by weight based on 100 parts by weight of the total weight of the components (A) to (D). More preferably, it is partially blended. The component (A1) is preferably compounded in an amount of 3 to 30 parts by weight, more preferably 3 to 25 parts by weight, based on 100 parts by weight of the total weight of the components (A) to (D). When the hot melt adhesive of the present invention contains the component (A1) in the above range, it is more excellent in the balance of adhesiveness to substrates such as paper, plastic and metal.

Component (B) is preferably compounded in an amount of 30 to 70 parts by weight, more preferably 40 to 60 parts by weight, based on 100 parts by weight of the total weight of components (A) to (D).
The 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 the total weight of the components (A) to (D). Most preferably, 20 to 30 parts by weight are blended.

  The component (D) is preferably blended in an amount of 1 to 40 parts by weight, more preferably 5 to 25 parts by weight, based on 100 parts by weight of the total amount of the components (A) to (D). Most preferably, 5 to 20 parts by weight is blended.

  In the hot melt adhesive of the present invention, when the component (E) is added, the component (E) is added in an amount of 0.1 to 1 part by weight relative to 100 parts by weight of the total weight of the components (A) to (D). It is preferable that 0.1 to 0.5 part by weight is added.

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

  When the viscosity at 160 ° C. is within the above range, the hot melt adhesive can be more easily and uniformly applied, and the adhesiveness between the straw package and the container is further improved. The viscosity (or melt viscosity) at 160 ° C. in this 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 rate of the hot melt adhesive and the initial cohesive force is further improved. The softening point was measured according to the ring and ball method.

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

  The hot melt adhesive of the present invention can be applied to an adherend. Since it is not necessary to add an organic solvent to the hot melt adhesive when coating, it is environmentally preferable.

  As the coating method, a generally well-known hot melt adhesive coating (or coating) method can be used, which is roughly classified into contact coating and non-contact coating. "Contact coating" refers to a coating method in which a sprayer is brought into contact with a member or film when applying a hot melt adhesive. "Non-contact coating" refers to applying a hot melt adhesive. In this case, it means a coating method in which the jetting machine is not brought into contact with 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, Examples include control seam coating, slot spray coating that can be applied to a surface, curtain spray coating, dot coating that can be applied in a dotted manner, and bead coating that can be applied in a linear manner.

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 that can be applied in the form of dots.
A hot melt adhesive is dot-coated on the straw packaging body or container side at 120 to 180 ° C., and the straw packaging body is attached to the container via the hot melt adhesive, so that 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 insertion hole 3 is formed in the upper surface 2 of the container 1 with a straw. A straw packaging body 6 is held by a hot melt adhesive (not shown) on the side surface of the container 1 with a straw. The straw wrapping body 6 encloses the straw 5 with a film of polyolefin or the like.

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

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

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely and in detail, these Examples are only one aspect | mode of this invention, and this invention is not limited at all by these examples.
In the description of the examples, unless otherwise specified, the portion not considering the solvent is used as the basis of parts by weight and% by weight.

The components used in this example are shown below.
(A) Thermoplastic block copolymer
(A1) Diblock-containing styrenic 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 T438 (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 Corporation, styrene content 45% by weight, diblock content 62% by weight)
(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 Polymer Co., Ltd., styrene content 30% by weight, diblock content 70% by weight)

(A2) Triblock styrene block copolymer
(A2-1) SBS (Tufprene 125 (trade name), manufactured by Asahi Kasei Chemicals Corporation, styrene content 40% by weight)
(A2-2) SBS (Tufprene A (trade name), manufactured by Asahi Kasei Chemicals Corporation, styrene content 40% by weight)
(A2-3) SBS (TR2250 (trade name), manufactured by JSR Corporation, styrene content 52% by weight)

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

(C) Softener
(C-1) Paraffin oil (Dafney Oil KP68 (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 (Sunpure N90 (trade name), manufactured by Sun Japan Oil Co., Ltd.)

(D) Wax
(D-1) Fischer-Tropsch wax (Sasol H1 (trade name), manufactured by Sasol)
(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 (Adeka Stub AO-412S (trade name), manufactured by Adeka)

Using a universal stirrer, the components (A) to (E) in the proportions (parts by weight) shown in Tables 1 to 3 were heated, melted and mixed at about 145 ° C. for about 1.5 hours, and Examples and Comparative Examples A hot melt adhesive was prepared.
About the above-mentioned hot melt adhesive, melt viscosity, softening point, adhesion performance to a paper pack and a plastic cup, and water-resistant adhesion performance using a paper pack were evaluated.
The sample preparation method, evaluation test method, and evaluation criteria for evaluation are described below.

<Viscosity measurement>
The hot melt adhesive was melted at 120 ° C., 140 ° C., 160 ° C. and 180 ° C., and after 20 minutes, the viscosity was measured using a No. 27 rotor using a Brookfield viscometer.
<Measurement of softening point>
The softening point of the hot melt adhesive was measured using a ring and ball method (method described in Japan Adhesive Industry Association Standard JAI-7-1999).

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

(Test method)
Using a universal tensile testing machine (manufactured by Shimadzu Corporation), a peel test was performed at a rate of 300 mm / min on the sample for adhesive strength evaluation prepared above. For each of the hot melt adhesives (Examples and Comparative Examples), measure at least three samples to obtain the value of each bond strength, calculate the average value thereof, and calculate the average bond strength value (simply “bond” Also called “strength”). Measured at each temperature of 5 ° C and 23 ° C.
Furthermore, about each sample, the peeling part was observed visually and the state was investigated.
The evaluation criteria for adhesive strength evaluation are shown below.

Adhesive strength evaluation A (excellent): average adhesive strength of 15 N or more B (good): average adhesive strength of 8 N or more to less than 15 N C (impossible): average adhesive strength of less than 8 N

State of peeled part (displayed to the right of A to C in adhesive strength evaluation)
++: Interface fracture (the surface of the substrate was destroyed)
+: Composite fracture in which interfacial fracture and cohesive fracture are mixed (breakage of both the substrate surface and adhesive)
*: Cohesive failure (adhesive was destroyed)
Higher adhesive strength is preferred (B is better than A and C is better than B), but interfacial failure is more preferable than cohesive failure between A and B.

  As shown in Tables 1 and 2, since the hot melt adhesives of Examples 1 to 12 include a component (A1): a styrenic block copolymer containing a diblock, at a low temperature (5 ° C.) and at a normal temperature ( 23 ° C.) and excellent water-resistant adhesive strength (with respect to paper packs and plastic cups). The hot melt adhesives of the examples are suitable for containers with straws because they have an excellent balance of performance.

As shown in Table 3, the hot melt adhesives of Comparative Examples 1 to 4 are either adherends (or base materials) at a low temperature (5 ° C.) when compared with the adhesives of Examples 1 to 12. In addition, 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 examples. Since the hot-melt adhesive of the comparative example has a water-resistant adhesive strength of C, it cannot be practically used for a container with a straw.
Therefore, since the hot melt adhesive contains a diblock styrene 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 coating 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 room temperature and low temperature, and also excellent in water-resistant adhesion. Is preferred.

1 Straw container 2 Surface 3 Straw hole 5 Straw 6 Straw package

Claims (5)

(A) 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 is a hot melt adhesive for a container with a straw, including a styrene block copolymer containing the component (A1): a diblock copolymer.   The hot melt adhesive according to claim 1, wherein the component (A1) contains a styrene block copolymer having a styrene content of 20 to 50% by weight and a diblock copolymer content of 20 to 80% by weight. Agent.   The hot melt adhesive according to claim 1 or 2, wherein the (A) thermoplastic block copolymer further comprises a component (A2): a triblock styrene block copolymer.   The hot melt adhesive according to any one of claims 1 to 3, further comprising (B) a tackifying resin, (C) a softening agent, and (D) a wax.   The container with a straw with which the straw is hold | maintained at the container with the hot-melt-adhesive in any one of Claims 1-4.

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