JP2002302894A - Emulsion-type adhesive for water-repellent paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an emulsion-type adhesive for water-repellent paper developing sufficient adhesive force even to a water-repellent paper subjected to high water-repelling treatment. SOLUTION: The emulsion-type adhesive for water-repellent paper contains 100 pts.wt. of an alkyl acrylate copolymer and an ethylene/vinyl acetate copolymer in total (usually each copolymer is present in both copolymers in an amount of 30-70 wt.%), >=5 pts.wt. of a urethane resin, 15-120 pts.wt. of a tackifier resin (preferably polymerized rosin), >=25 pts.wt. of limonene or hydrogenated limonene, and >=1 pt.wt. of a dialkyl sulfosuccinate. The adhesive may further contain >=20 wt.% alcohol based on the limonene or the hydrogenated limonene.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emulsion-type adhesive for water-repellent paper, and has excellent initial adhesive strength, adhesive strength after film formation, water resistance, etc., even on processed paper having high water repellency. Emulsion type adhesive.

[0002]

2. Description of the Related Art Conventionally, emulsion adhesives have been widely used as paper adhesives. However, since the emulsion-type adhesive usually contains water, there is a problem that when the water-repellent paper which has been subjected to the water-repellent processing with wax or the like is bonded, the adhesive is not sufficiently wetted on the paper surface and interfacial peeling occurs. was there.

Therefore, an emulsion type adhesive containing a vinyl acetate resin emulsion and kerosene has been proposed as an emulsion type adhesive capable of adhering even water-repellent paper (Japanese Patent Application Laid-Open No. 59-91166).

Further, as a raw material paper used for a paper container for wrapping a material which is unavoidable to be wet with water during transportation and storage or a material which is sensitive to moisture, a moisture resistant processed paper having a polyethylene film layer therein has been widely used. However, since the polyethylene film layer hinders the reuse of paper resources, the use of water-repellent paper treated with a wax or the like made of a mixture of paraffin and acrylic resin has been studied. I have.

[0005]

However, according to the study of the present inventors, the emulsion type adhesive described in the above publication has a problem that the initial adhesive strength is insufficient and the adherends are displaced from each other on the adhesive surface. If the paper is simply water-repellent to the extent of using paraffin wax, it can be adhered, but advanced water-repellent treatment using wax or the like made of a mixture of paraffin and acrylic resin is applied. However, there is a problem that sufficient water-repellent paper cannot provide sufficient adhesive strength.

The present invention has been made in view of the above-mentioned problems of the conventional emulsion type adhesive for water-repellent paper, and has as its object to provide a water-repellent paper which has been subjected to a high water-repellent treatment. Another object of the present invention is to provide an emulsion type adhesive for water-repellent paper which can exhibit a sufficient adhesive strength.

[0007]

In order to achieve the above-mentioned object, the invention according to claim 1 is directed to an invention wherein the total amount of the acrylate-based copolymer and the ethylene-vinyl acetate-based copolymer is 10%.
5 parts by weight or more of urethane resin, 15 to 120 parts by weight of tackifier resin, 25 parts by weight or more of limonene or hydrogenated limonene, and 1 part by weight or more of dialkyl sulfosuccinate relative to 0 parts by weight. The present invention provides an emulsion adhesive for water-repellent paper, which further comprises 20% by weight or more of an alcohol based on the limonene or hydrogenated limonene.

According to a second aspect of the present invention, the acrylate ester copolymer is obtained by copolymerizing an alkyl (meth) acrylate having 2 to 12 carbon atoms in the alkyl group.
An emulsion type adhesive for water-repellent paper according to claim 1 is provided. The invention according to claim 3 provides the emulsion-type adhesive for water-repellent paper according to claim 1 or 2, wherein the ethylene content of the ethylene-vinyl acetate copolymer is 15 to 40% by weight. The invention according to claim 4 provides the emulsion adhesive for water-repellent paper according to any one of claims 1 to 3, wherein the tackifier resin is a polymerized rosin-based resin.

Hereinafter, the present invention will be described in more detail. The acrylic ester-based copolymer in the present invention refers to alkyl (meth) acrylates or alkyl (meth) acrylates.
It refers to a copolymer of an acrylate and a polymer monomer copolymerizable with the alkyl (meth) acrylate. As the alkyl (meth) acrylate, an alkyl (meth) acrylate having 2 to 12 carbon atoms in an alkyl group is usually used. Used. When the number of carbon atoms of the alkyl group of the alkyl (meth) acrylate is less than 2, the adhesion of the obtained emulsion type adhesive to an adherend and the initial adhesive strength may be insufficient. If the number exceeds 12, the cohesive force of the dried film of the obtained emulsion-type adhesive is reduced, and the adhesive strength and heat resistance may be insufficient. In addition, in this specification, for example, alkyl (meth) acrylate means alkyl acrylate and / or alkyl methacrylate.

Preferred alkyl (meth) acrylates having 2 to 12 carbon atoms in the alkyl group include, for example, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and the like. Examples of the monomer copolymerizable with the alkyl (meth) acrylate include (meth) acrylic acid, methyl (meth) acrylate, and ethylene glycol (meth) acrylate, and are preferably used.

The ethylene-vinyl acetate copolymer in the present invention is obtained by copolymerizing ethylene and vinyl acetate and, if necessary, is copolymerized with another copolymerizable monomer. May be. The ethylene content in the ethylene-vinyl acetate copolymer is preferably 15 to 40% by weight, more preferably 20 to 3% by weight.
5% by weight. If it is less than 15% by weight, the adhesiveness to the water-repellent surface may be reduced, and if it exceeds 40% by weight, it may be difficult to obtain a stable product as an industrial product.

In the emulsion type adhesive of the present invention,
The acrylate-based copolymer is usually used in the form of an acrylate-based copolymer emulsion,
The ethylene-vinyl acetate copolymer is usually used in the form of an ethylene-vinyl acetate copolymer emulsion.

In the adhesive of the present invention, the acrylate-based copolymer and the ethylene-vinyl acetate-based copolymer are preferably 30 to 30 acrylate-based copolymers based on the total amount of both copolymers. It is used in a proportion of 70% by weight and 70 to 30% by weight of an ethylene-vinyl acetate copolymer.

The type of the urethane resin in the present invention is not particularly limited. The content of the urethane resin is based on 100 parts by weight of the total amount of the acrylate ester copolymer and the ethylene-vinyl acetate copolymer. 5 parts by weight or more is required, and preferably 10 to 30 parts by weight. If the amount is less than 5 parts by weight, the initial adhesive strength is poor and the adhesiveness to the water-repellent surface is extremely poor.

Incidentally, the urethane resin in the present invention is also usually used in the form of an emulsion, and 5 parts by weight based on 100 parts by weight of the total amount of the acrylate copolymer and the ethylene-vinyl acetate copolymer. The above means a value based on each resin component, that is, based on a dry weight of each resin component.

The urethane resin emulsion is prepared, for example, by dissolving a polyol and a polyisocyanate compound in a predetermined ratio in an organic solvent, synthesizing a urethane prepolymer by a boiling point polymerization method or the like, and then using a high-speed stirrer such as a homomixer or a disper. The compound can be obtained by adding a compound having a functional group capable of reacting with an isocyanate group and water while stirring vigorously to emulsify while performing a urethanization reaction, and finally removing the solvent under reduced pressure.

The type of the tackifier resin in the present invention is not particularly limited as long as it does not impair the effects of the present invention. Examples thereof include a polymerized rosin resin, a terpene resin, and an aliphatic petroleum resin. And aromatic petroleum resins, coumarone resins, alkylphenol resins, xylene resins, and the like. Polymerized rosin resins are preferably used in terms of compatibility and the like in the adhesive of the present invention. The content is required to be 15 to 120 parts by weight, preferably 45 to 75 parts by weight, based on 100 parts by weight of the total amount of the acrylate-based copolymer and the ethylene-vinyl acetate-based copolymer.
When the amount of the tackifying resin to be blended is less than 15 parts by weight, the adhesiveness to the water-repellent surface is extremely reduced, and when it exceeds 120 parts by weight, the low-temperature adhesiveness is reduced.

Tackifying resins such as the above-mentioned polymerized rosin-based tackifying resins are usually used in the form of an emulsion, and the total amount of the acrylate-based copolymer and the ethylene-vinyl acetate-based copolymer is 100%. With respect to parts by weight, 15 to 120 parts by weight is based on each resin component.
That is, it means, of course, a value based on the dry weight of each resin.

The emulsion type adhesive for water-repellent paper of the present invention contains limonene or hydrogenated limonene and dialkyl sulfosuccinate in addition to the above-mentioned components. The limonene is a liquid hydrocarbon at normal temperature represented by the following formula (1), and the hydrogenated limonene is a hydrogenated limonene. The limonene and hydrogenated limonene may each be used alone,
Both may be used together.

[0020]

Embedded image

The content of limonene or hydrogenated limonene is determined by the above-mentioned acrylate-based copolymer and ethylene-
For a total amount of 100 parts by weight of the vinyl acetate copolymer,
25 parts by weight or more. If it is less than 25 parts by weight, the water resistance is poor and the adhesion to the water-repellent surface is extremely poor. Also, there is no particular upper limit on limonene to be blended,
Care must be taken because adding a large amount of odor increases the odor.

The dialkyl sulfosuccinate ester salt is a calcium salt or a sodium salt of sulfosuccinic acid in which an atomic group of sulfosuccinic acid is present at the center of the molecule and the sulfosuccinic acid is esterified with various alcohols.
It is a so-called anion (anion) type surfactant. These dialkyl sulfosuccinate salts may be used alone or in combination of two or more.

The content of the dialkyl sulfosuccinate is not less than 1 part by weight based on 100 parts by weight of the total of the acrylate ester copolymer and the ethylene-vinyl acetate copolymer. If the amount is less than 1 part by weight, the wettability of the adhesive to the water-repellent surface is deteriorated, and the adhesive strength is reduced. In addition, the upper limit of the amount of the dialkyl sulfosuccinate to be added is not particularly recognized, and even if a large amount is added, the effect is not particularly changed.

The emulsion type adhesive for water-repellent paper of the present invention further contains an alcohol in addition to the above. As the alcohol, one having 1 to 4 carbon atoms is usually used. The content of the alcohol is 20% by weight or more based on the amount of the limonene or the hydrogenated limonene. If it is less than 20% by weight, the adhesive strength at low temperatures will be extremely reduced. There is no particular upper limit for the alcohol to be blended, but care must be taken as a large amount of alcohol lowers the boiling point of the adhesive of the present invention.

(Effect) Since the emulsion adhesive for water-repellent paper of the present invention is an emulsion containing an acrylate-based copolymer and an ethylene-vinyl acetate-based copolymer, it has excellent initial adhesive strength. As well as having a high cohesive force of the dried film, it exhibits excellent normal-state adhesive strength. In addition, the urethane resin enhances the initial adhesive strength and improves the adhesiveness to the water-repellent surface, and the tackifier resin exhibits high adhesiveness to the wax-treated surface and the like. Further, since limonene or hydrogenated limonene is contained, the water resistance is increased, and the adhesion to the water-repellent surface can be improved. In addition, dialkyl sulfosuccinate ensures the adhesive wettability to the water-repellent surface, further improving the adhesive force to the water-repellent surface, and exhibits excellent low-temperature adhesiveness due to the inclusion of alcohol. can do.
Together with the actions of the above components, the adhesive of the present invention has excellent adhesiveness even on a surface subjected to a high water-repellent treatment using a wax or the like made of a mixture of paraffin and an acrylic resin. Can be demonstrated.

[0026]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples. Example 1 Acrylic ester copolymer emulsion [butyl acrylate-2-ethylhexyl acrylate-acrylic acid terpolymer emulsion] and ethylene-vinyl acetate copolymer emulsion (trade name "S
F-950 "manufactured by Sumitomo Chemical Co., Ltd., ethylene-vinyl acetate-veova terpolymer, ethylene content 20% by weight)
To 100 parts by weight of the resin mixture (each resin ratio of acrylate ester copolymer emulsion / ethylene-vinyl acetate copolymer emulsion = 5/5) to a urethane resin emulsion (trade name “UPLENE 306”). "Sanyo Kasei Co., Ltd.) in terms of resin content, 20 parts by weight, polymerized rosin-based tackifier (trade name" Super Ester E-650 ")
70 parts by weight of resin (Arakawa Chemical Co., Ltd.) and 3 parts of limonene (trade name "D-limonene" manufactured by Yashara Chemical Co., Ltd.)
0 parts by weight, 1.5 parts by weight of dialkyl sulfosuccinate (trade name "Sammorin OT-70" manufactured by Sanyo Chemical Co., Ltd.), 2-
After adding 22% by weight of propanol (isopropanol) to the amount of limonene added, the viscosity was adjusted with a thickener or the like to obtain an emulsion adhesive having a viscosity of 3,000 mPa · s and a nonvolatile content of 38% by weight.

Example 2 An emulsion adhesive having a viscosity of 2,800 mPa · s and a non-volatile content of 38% by weight was obtained in exactly the same manner as in Example 1 except that the blended limonene was changed to 50 parts by weight. . (Example 3) Except that the blended limonene was changed to hydrogenated limonene, the viscosity was 3,000 in the same manner as in Example 1.
An emulsion adhesive having mPa · s and a nonvolatile content of 38% by weight was obtained.

Example 4 An emulsion-type adhesive having a viscosity of 2,800 mPa · s and a non-volatile content of 39% by weight was obtained in exactly the same manner as in Example 2 except that the blended limonene was changed to hydrogenated limonene. .

(Comparative Example 1) An ethylene-vinyl acetate copolymer emulsion (trade name) was used instead of the mixture of the acrylate copolymer emulsion and the ethylene-vinyl acetate copolymer emulsion used in Example 1. OM-
Example 1 except that "4000" manufactured by Kuraray Co., Ltd.) was used.
In the same manner as above, an emulsion adhesive having a viscosity of 2,800 mPa · s and a nonvolatile content of 40% by weight was obtained.

Comparative Example 2 An emulsion adhesive having a viscosity of 2,500 mPa · s and a non-volatile content of 43% by weight was obtained in exactly the same manner as in Example 1 except that the blended limonene was changed to 10 parts by weight. . (Comparative Example 3) Except that ethyl acetate was used instead of the blended limonene, the viscosity was 3,
An emulsion-type adhesive having a viscosity of 000 mPa · s and a nonvolatile content of 38% by weight was obtained. The content of 2-propanol (isopropanol) is 22% by weight of the amount of ethyl acetate added.

Comparative Example 4 An emulsion adhesive having a viscosity of 2,900 mPa · s and a nonvolatile content of 38% by weight was prepared in the same manner as in Example 1 except that the blended urethane resin emulsion was changed to 1 part by weight. Obtained. (Comparative Example 5) An ethylene-vinyl acetate copolymer emulsion (trade name "OM-4000" manufactured by Kuraray Co., Ltd.) was used instead of the mixture of the acrylic emulsion and the ethylene-vinyl acetate copolymer emulsion used in Example 1. Using
An emulsion adhesive having a viscosity of 2,400 mPa · s and a non-volatile content of 38% by weight was obtained in exactly the same manner as in Example 1 except that kerosene was used instead of limonene. The content of 2-propanol (isopropanol) is 22% by weight of the amount of kerosene added.

(Comparative Example 6) Except that the blended dialkyl sulfosuccinate was used in an amount of 0.5 part by weight, the viscosity was 3,200 mPa · s and the nonvolatile content was 3 in the same manner as in Example 1.
8% by weight of an emulsion adhesive was obtained. (Comparative Example 7) Except that the content of the blended 2-propanol (isopropanol) was 10% by weight of the added amount of limonene, the viscosity was 3,000
An emulsion adhesive having 0 mPa · s and a nonvolatile content of 40% by weight was obtained.

(Comparative Example 8) Except that the added amount of the polymerized rosin-based tackifier was 5 parts by weight in terms of resin, the viscosity was 2,800 mPa.
-An emulsion-type adhesive having a non-volatile content of 38% by weight was obtained. (Comparative Example 9) Except that the added amount of the polymerized rosin-based tackifier was 150 parts by weight in terms of resin, the viscosity was 2,800 mPa · s, and the nonvolatile content was 38 parts by weight. % Of an emulsion type adhesive was obtained.

(Evaluation of Performance) The performance of the obtained emulsion type adhesive was evaluated by the following method. The water-repellent paper used in the evaluation was liner paper (water repellency: 10) whose surface was highly water-repellent with wax or the like. Normal (shear) adhesive force As an adherend, two sheets of water-repellent paper cut to a width of 25 mm and a length of 50 mm are prepared, and an adhesive area of 25 mm × 25 mm is applied to the water-repellent treated surface of one of the water-repellent papers. After applying the emulsion adhesive so that the amount (wet) becomes 50 g / m ² , the water-repellent treated surface of the other water-repellent paper is stuck on the emulsion adhesive in a staggered manner. Then, pressure bonding was performed at a pressing pressure of 14.7 kPa to produce an adhesive test piece. After curing this adhesive test piece in an atmosphere of 20 ° C.-65% RH for 72 hours, a tensile test was performed using a tensile tester (trade name “Instron 1195”, manufactured by Instron) at a tensile speed of 100 mm / min. And the normal (shear) adhesive force (N / cm ² ) was measured. At the same time, the material destruction rate (area%) of the water-repellent paper at the bonded portion was measured.

Low-Temperature (Shear) Adhesive Force The same test specimen as above was bonded in an atmosphere of 0 ° C., and pressed at a pressing pressure of 14.7 kPa to produce an adhesive test specimen. The adhesive test piece was placed in an atmosphere of 5 ° C. and 50% RH for 2
After curing for 4 hours, a tensile test was performed at a tensile speed of 100 mm / min using a tensile tester (trade name “Instron 1195”, manufactured by Instron) under an atmosphere temperature of 5 ° C. and 50% RH. And low temperature adhesive strength (N / cm ² ) were measured. At the same time, the material destruction rate (area%) of the water-repellent paper at the bonded portion was measured.

Initial Adhesive Strength (Shear Adhesive Strength) As an adherend, a width of 40 mm × length of 100 mm and a width of 50 m
Prepare a water-repellent paper cut to mx 100 mm in length.
In an atmosphere of 2 ° C. and 50% RH, the water-repellent treated surfaces of the water-repellent treated paper were alternately adhered to each other with an emulsion adhesive (shear adhesion type) to prepare an adhesion test piece. Then
The initial shear adhesive strength (N / cm ² ) was measured using an initial adhesive strength measuring device (manufactured by JT Toshi). The bonding conditions and measurement conditions at this time were as follows. [Adhesion conditions] Adhesion area: 40 mm × 40 mm, application amount (wet): 50 g / m ² Application speed: 0.6 m / sec, open time: 5 seconds,
Clamping pressure: 294 kPa Clamping time: 3 conditions of 10 seconds, 20 seconds, and 30 seconds [Measurement conditions] Leaving time after decompression: 3 seconds, tensile speed: 100
mm / min, measurement temperature and humidity: 20 ° C. × 65% RH

An adhesive test piece prepared in the same manner as in the case of water resistance (fall time) was heated at 20 ° C.-6
After being cured in an atmosphere of 5% RH for 72 hours, the adhesive test piece was vertically immersed in water at 20 ° C. while a weight of 100 g was suspended at the lower end of one of the water-repellent papers (substrate). ,
The time required for the water-repellent paper (substrate) to peel off on the adhesive surface and to fall (fall time: time) was measured.

Wettability An emulsion-type adhesive was applied to the water-repellent surface of the water-repellent paper with a doctor blade having a thickness of 25 μm, and the wettability of the adhesive was visually evaluated on a five-point scale according to the following criteria. The larger the number, the better the wettability. Table 1 shows the evaluation results of Examples 1 to 4 and Comparative Examples 1 to 9.

[0039]

[Table 1] According to Table 1, in the emulsion adhesive for water-repellent paper of the present invention, as shown in Examples 1 to 4, Comparative Examples 1 to 9
For normal (shear) adhesion, low temperature (shear) adhesion,
It can be seen that it has excellent initial adhesive strength and the like, and exhibits well-balanced performance including water resistance and wettability.

[0040]

The emulsion type adhesive for water-repellent paper of the present invention is constituted as described above, and is an acrylate ester-based adhesive having an effect of increasing initial adhesive strength, cohesive strength, adhesive strength after film formation and the like. Urethane resin, tackifying resin, limonene or hydrogenated limonene, which exhibits an effect on initial adhesion, adhesion to a water-repellent surface, water resistance, etc. for a mixture of a copolymer and an ethylene-vinyl acetate copolymer. In addition to an emulsion-type adhesive containing a dialkyl sulfosuccinate in a well-balanced manner, an alcohol that can particularly enhance low-temperature adhesion is further contained, so that a water-repellent material highly water-repellent by wax or the like is used. Although it is an emulsion adhesive containing water, it can exhibit extremely excellent and well-balanced adhesion to water-processed paper. This makes it possible to provide an emulsion-type adhesive for water-repellent paper, in which the adherends are not displaced from each other on the adhesive surface and sufficient adhesive strength can be obtained.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C09J 193/04 C09J 193/04 D21H 19/20 D21H 19/20 Z F term (reference) 4J040 BA202 DA051 DE031 DF041 DF051 DK012 DN032 DN072 EB052 EL012 FA032 HB02 HB08 HD13 JA03 KA26 LA06 LA07 MA09 4L055 AG50 AG59 AG64 AG71 AG89 AG97 AG99 AH23 AH37 BE08 FA30 GA47

Claims (4)

[Claims] An urethane resin and a tackifying resin are used in an amount of at least 5 parts by weight based on 100 parts by weight of the total amount of the acrylate ester copolymer and the ethylene-vinyl acetate copolymer.
5 to 120 parts by weight, 2 parts of limonene or hydrogenated limonene
An emulsion-type adhesive for water-repellent paper containing at least 5 parts by weight of dialkyl sulfosuccinate and at least 1 part by weight of dialkyl sulfosuccinate, further comprising at least 20% by weight of alcohol based on the limonene or hydrogenated limonene. An emulsion-type adhesive for water-repellent paper, characterized by being made. 2. The water-repellent material according to claim 1, wherein the acrylate copolymer is obtained by copolymerizing an alkyl (meth) acrylate having 2 to 12 carbon atoms in the alkyl group. Emulsion adhesive for processed paper. 3. The emulsion-type adhesive for water-repellent paper according to claim 1, wherein the ethylene content of the ethylene-vinyl acetate copolymer is 15 to 40% by weight. 4. The emulsion-type adhesive for water-repellent paper according to claim 1, wherein the tackifier resin is a polymerized rosin-based resin.