JPS60147486A - Water-based polyester adhesive - Google Patents

Abstract

PURPOSE:The titled adhesive that is obtained by using a specific polyester resin, a specific (meth)acrylate copolymer, a water-soluble organic solvent and a surface active agent in a specific proportion, thus being suitably used for aluminum foil and paper, because it is excellent in adhesion, blocking resistance and clarity. CONSTITUTION:The objective adhesive is prepared by mixing (A) a polyester resin containing sulfonate salts and/or carboxylate salt such as terephthalate in the molecule and having 2,500-30,000 molecular weight, (B) a (meth)acrylate copolymer containing acrylate and/or methacrylate salts such as Li salt and having a Tg of 5-105 deg.C, (C) a water-soluble organic solvent boiling at 60- 200 deg.C, (D) a surface active agent and (E) water so that the following equations are satisfied: A+B+C+D+E=100, A+B=5-70, B/A=0.01-2, C=0-50 and D=0-10. EFFECT:Heat-sealing properties and moisture resistance are improved. USE:An adhesive for giving heat-sealing properties to biaxially stretched polypropylene films, paper and so on.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-sealing adhesive for imparting heat-sealing properties to biaxially oriented polypropylene films, other plastic films, aluminum, and paper. An object of the present invention is to obtain a water-based adhesive that can replace the organic solvent-type adhesives of 2008 and which satisfies the adhesive strength, blocking resistance, etc. generally required in the market.

Among the plastic films used for food packaging such as rice crackers, snacks, and dried sweets, as well as for various other packaging, apart from polyethylene film, which itself has heat-sealing properties, biaxially oriented polypropylene film, polyester film, etc. Since it does not have heat sealability, it is necessary to provide heat sealability. - In the case of a stretched polypropylene film, heat-sealability can be imparted by coating the surface with a heat-sealing adhesive or by laminating an unstretched polypropylene film on the surface by extrusion. Currently used heat-sealing adhesives for coating surfaces include chlorinated polycarbonate, lipo-pyrene, vinyl chloride/vinyl acetate copolymer, and vinylidene chloride. Chlorinated propylene and vinyl chloride/vinyl acetate copolymer are resins dissolved in organic solvents such as toluene.
Water-based adhesives are desired from the standpoint of pollution and fire. Vinylidene chloride has poor adhesion to biaxially oriented polypropylene film, so it has the disadvantage that an anchoring agent must be coated between the polypropylene film and the heat seal adhesive.

The present inventors have worked diligently to develop a heat-sealing adhesive that is water-based and has adhesive properties to biaxially oriented polypropylene films, and also satisfies the required conditions such as heat-sealability, blocking resistance, transparency, and moisture resistance. As a result of this study, we have completed the present invention.

The heat-sealing adhesive of the present invention has (A) a molecule 'II containing a sulfonate and/or a carboxylate in the molecule;
L2500-3ooOo Bo'):t:Xf resin, (
B) Tg containing acrylate and/or methacrylate in the molecule is 5 to 105°C, preferably 30 to 80°C
(meth)acrylic acid ester copolymer resin, (0) a water-soluble organic solvent with a boiling point of 60 to 200"C, (D) a surfactant, and (to) a mixture of water, and a mixture of these components. The proportion (based on weight) satisfies the following formula.

(A) + (B) + (0) + (D) + (II = 100
(A) + (B) 5-70 (B)'/ (A) 50.01-2 (0) 0-50 (D) -0-10 (K) = 1 5-95 Heat of the present invention Stretched polypropylene films coated with adhesive and dried exhibit adhesive strength comparable to that of chlorinated polypropylene.

Furthermore, the heat-sealing adhesive of the present invention has sufficient adhesion properties, so it can fully compete with conventional solvent-based heat-sealing adhesives. Of course, it can also be used as an anchor coating agent.

In the present invention (the polyester resin used as a gradient component), the polycarboxylic acid component is 30 to 100 mol% of an aromatic dicarboxylic acid containing no sulfonic acid metal base, 70 to 0 mol% of an aliphatic or dicarboxylic acid and a sulfonic acid metal base. Contains less than 30 mol of aromatic dicarboxylic acid, polyol component is aliphatic glycol or/and dried fish 2,500 to 30,000.Carboxyl group concentration is 140K
A polyester resin having an oaq/P or less is preferable.

Examples of aromatic dicarboxylic acids that do not contain sulfonic acid gold #1 base include terephthalic acid, isophthalic acid, orthophthalic acid, and the like. It is necessary that the sulfonic acid is an aromatic shikamol group that does not have a metal base. If it is less than 30 mol%, the mechanical strength and weather resistance of the polyester resin will be poor, which is not preferable.

Examples of aliphatic or alicyclic dicarboxylic acids include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, tetrahydrophthalic acid, hexahydrophthalic acid, hexahydroisophthalic acid,
Examples include hexahydroterephthalic acid.

The aliphatic or cycloaliphatic dicarboxylic acid accounts for 70 to Q mole percent of the polycarboxylic acid component. If it exceeds 70 mol%, water resistance and coating strength will decrease and tackiness will appear. Furthermore, p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, hydroxypivalic acid, r-butyrolactone, ε-caprolactone, etc. can be used as necessary. Further, if necessary, a trifunctional or higher functional polycarboxylic acid such as trimellitic acid or pyromellitic acid may be used in an amount of 10 mol % or less based on the total polycarboxylic acid component.

Aliphatic glycols include ethylene glycol, 1,2
-propylene glycol, 1,3-propanediol,
l, 4-butanediol, diethylene glycol, neopentyl glycol, 1,5-bentanediol, 1,
6-hexanediol and the like can be mentioned. Examples of the alicyclic glycol having 6 to 12 carbon atoms include 1,4-cyclohexane dimetatool. Carbon number 2
-8 aliphatic glycol or/and carbon number 6-12
The alicyclic glycol content is 90 to 90% of the total polyol component.
It is 100 mol%. Further, if necessary, a trifunctional or higher functional polyol such as trimethylolpropane, trimethylolethane, glycerin, pentaerythritol, etc. may be present in an amount of 10'-T or less based on the total polyol component.

Furthermore, polyalkylene glycol, especially molecular weight 100
Polyethylene glycol having a molecular weight of 0.00 or less may be used if necessary in an amount of 20% by weight or less based on the total polyol component cloud ζ. If the content of polyalkylene glycol, particularly polyethylene glycol, exceeds 20 mol%, the water resistance and weather resistance of the Berryester resin will be extremely reduced.

Examples of dicarboxylic acids containing sulfonic acid paulownia groups include sulfoterephthalic acid, 5-sulfoinphthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid,
5 (Metal salts such as 4-sulfophenoxyfuisophthalic acid can be mentioned.As metal salts, Li*Na
Examples include l K I Mg + salts such as Oa, Ou, and Fs. Particularly preferred is 5-sodium sulfoisophthalic acid. Sulfonic acid metal base-containing aromatic dicarboxylic acid contains 3% of the total polycarboxylic acid components.
It is less than 0 mol %, preferably less than 10 mol %, based on the total polycarboxylic acid component.

As the amount of the metal base-containing aromatic dicarboxylic acid increases, better dispersibility is exhibited.

However, if the amount exceeds 30 mol %, the resulting polyester resin has good dispersibility in water, but the water resistance of the film obtained after coating and drying becomes very poor.

Examples of the carboxylic acid salts contained in the molecular chain of the polyester resin of the present invention include aromatic polycarboxylic acids such as terephthalic acid, inphthalic acid, orthophthalic acid, trimellitic acid, and pyromellitic acid, as well as succinic acid, adipic acid, cepatic acid,
Id and a carboxyl group intentionally introduced at the end of the -ζ molecular chain by an aliphatic polycarboxylic acid such as azelain.

Na, K, Mg, Oa, Ou, It
Further, 1ζ may be organic salts with amine derivatives such as ammonia, monomethylamine, diethylamine, monoethylamine, diethylamine, monoethanolamine, jetanolamine, etc. 7: The carboxyl group concentration of the polyester resin of the invention is 140 xoHWv/P or less, preferably 94
The range is below KOH1q/f. 1 carboxyl group
If it exceeds 40 KOHW/f/, stable aqueous polyester resin cannot be obtained. 140 as a carboxylate
Any concentration can be used as long as it is below KOHwg/f.

In the present invention, polyester resins can be used alone or in combination of two or more types if necessary.

The molecular weight of the polyester resin of the present invention is 2500 to 300
00, particularly preferably 3000 to 2000
It is 0. If the molecular weight is less than 2,500, the mechanical properties of the obtained film, especially the flexibility, will be poor, which is not preferable.

Furthermore, if the molecular weight exceeds aooooo, the viscosity of the aqueous dispersion increases, making it difficult to increase the content of the polyester resin.

The polyester resin used in the present invention can be produced by any known method. Further, the polyester resin thus obtained can be mixed in a molten state or (in a solution state with a water-soluble organic compound described later) with a resin, an epoxy compound, an incyanate compound, etc. Alternatively, it is also possible to partially react with these compounds, and the resulting partial reaction product can also be used as a raw material for an aqueous dispersion.

The acrylic ester copolymer resin used as component (B) for the first time in the present invention preferably contains an acrylic ester or/and a methacrylic ester as a 7-mer component, and an acrylic acid salt and/or a methacrylic acid. Tg consisting of 10-0 mol% salt is 5-105
℃ copolymer resin. Examples of acrylic esters include methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and examples of methacrylic esters include methyl methacrylate, ethyl methacrylate, and butyl methacrylate. Acrylates and methacrylates include metal salts such as Li, Ha, and K, and organic salts such as ammonia, monoethanolamine, jetanolamine, and the like.

The water-bathable organic solvent used as component (0) in the present invention is preferably an organic solvent having a solubility in 1 ton of wood incense at 20°C or higher, and the specific number ζ is an aliphatic and alicyclic alcohol. , ether, ester and ketone compounds. Specifically, for example, methanol, ethanol, n-propanol, 1-propanol,
Monohydric alcohols such as n-butanol, j-butanol, 5ea-butanol, tart-butanol, glycols such as ethylene glycol and propylene glycol, methyl cellosolve, methyl cellosolve, n-butyl cellosolve, tert-butyl cellosolve, 3-methyl-
3-methoxybutanol, n-butyl cellosolve acetate, glycols, conductors, dioxane, ethers such as tetrahydrofuran) q% ethyl acetate, ketones such as methyl ethyl ketone, cyclohexanone, cyclooctanone, cyclodecanone, isophorone, etc. Particularly preferred are n-butyl cellosolve,
Ethyl Ceroso.

Lube, Improper Tools, etc. 1 tN of these 8 water
m compounds can be used alone or in combination of two or more. The heating point of these water i# + IA solvents is 60 to 200.
It is necessary that the temperature be within the range of ℃. If the cape point does not reach 60° C., it is difficult to maintain a temperature sufficient to mix or dissolve the polyester resin in this dry compound. Further, if the boiling point is higher than 200° C., the resulting aqueous dispersion cannot be dried quickly after being applied.

In addition, when a nistyl sulfonate compound is used as a water-soluble compound in the amide resin, the drying properties are poor and the storage stability of the water-based resin is also poor.

The contact M strength of the adhesive of the present invention largely depends on the polyester resin as the component (4). This polyester 41
[ has strong adhesion to biaxially oriented polypropylene and other plastics, and also rapidly melts at around 100'C and exhibits heat sealability. (B) Component acrylic 11B
'fl.' has the meaning of improving slipperiness and the effect of improving adhesive strength. The total amount of polyester resin and acrylic resin is 5 to 70% by weight, preferably 10 to 50% by weight based on the total amount of adhesive.
The weight is j and the acrylic/polyester ratio is 0.01
-2, preferably 0.05-0.5.

If the acrylic/polyester ratio is less than 0.05, the adhesive strength will decrease, and if it is more than 0.5, the adhesive strength and water resistance will decrease. Component (Q), a water-soluble organic solvent, has the effect of improving wettability when applying an adhesive to a film. The mixing ratio is 0 to 50% by weight based on the total amount of adhesive,
Preferably it is 2 to 30% by weight. The surfactant component (D) is also used to improve wettability. These include nonionic activators and anionic activators, and fluorine-based activators are particularly effective even when added in small amounts. Cationic activators cannot be used because they have poor compatibility with resins. The mixing ratio is 0 to 10% by weight, preferably 0.01 to 1% by weight, based on the total amount of the adhesive. If the amount added is too large, adhesive strength, water resistance, etc. will deteriorate, which is not preferable.

(The mixing ratio of water as a noble component is 15 to 9% of the total amount of adhesive.)
5% by weight, preferably 50-90% by weight. If it is less than 15% by weight, the viscosity of the water-based polyester thread adhesive will be high, resulting in poor coating properties and poor drying properties. 95 again
If the percentage of heavy wax is exceeded, the viscosity becomes low and the desired coating thickness cannot be obtained.

The water-based polyester thread heat-sealing adhesive of the present invention, which is composed of a mixture of the above (4) to (binding), is a stable aqueous dispersion that does not separate or precipitate, and its performance does not change for at least one year. Application to a film This can be done using either the gravure method or the doctor method, and no matter how much the amount of coating is reduced, there is no repelling and the coating can be uniformly applied.The dried and rolled film has excellent heat seal strength, anti-blocking properties, transparency, It exhibits good physical properties in terms of water resistance, slipperiness, etc. Examples will be described below.

Measurement method 0 Application amount Calculated from the difference in weight of the film before and after application O
Transparency Judging by naked eye 0 Slip property Judging by touch 0 Humidity 40℃, 90%RH, 24 hour production example
1. Charge 115 parts of dimethyl terephthalate, 75 parts of dimethyl inphthalate, 71 parts of ethylene glycol, 110 m of neopentyl glycol, 0.1 part of zinc acetate and 0.1 part of antimony trifluoride into a reaction container,
The transesterification reaction was carried out at ℃ for 3 hours. Next, 10.0 parts of 5-sodium sulfoiphthalic acid was added and the esterification reaction was carried out at 220 to 260°C for 1 hour.
Polycondensation reaction was carried out at 1Hg) for 2 hours to form molecule 3.
913200, carboxyl group concentration 3.4KOHIIF
/P, a polyester resin (A-1) having a softening point of 157°C was obtained.

Production example 2 38 parts of dimethyl terephthalate, 71 L' of dimethyl ia
-) 152%, A polyester resin (A-2) having a temperature of 115°C was obtained.

Example 1 Polyester resin (A-1) was used as the polyester resin, and MMA/MA/MAA was used as the water-soluble acrylic resin.
A copolymer of 61/36/3 was mixed with ethyl cellosolve as a water-soluble organic solvent and Florado FO as a surfactant.
-129 (a fluorine-based surfactant manufactured by 3M Co., Ltd.) was used. The acrylic resin/polyester ratio is 0.18, and the total amount of acrylic resin and polyester is 15%.
Ethyl cellosolve is 6.5% by weight, Florado Va-1
29 is 0.1% by weight. The pH of the liquid was adjusted to 8.1 using 28% aqueous ammonia. The yield was 40p8.

The above heat-sealing adhesive was coated with a Mayer bar A8 onto a biaxially oriented polypropylene film having a thickness of 20 μm and which had been subjected to corona discharge treatment on one side. The coated film was dried with hot air at 80° C. for 30 seconds. The heat seal strength, blocking resistance, etc. of the obtained film were measured. The results are shown in the table. Example 2 Polyester resin (A-2) was used as the polyester resin, acrylic resin similar to Example 1 was used as the acrylic resin, and the acrylic resin/polyester ratio was set to 0.11. , the total amount of resin was 15 layers. 5% by weight of Improper Tool was used as a water-soluble organic solvent, and 0.1% by weight of Florard FO-129 was used as a surfactant.

This was coated on a biaxially stretched poly(19) propylene film in the same manner as in Example 1, and performance evaluation was performed, and good results were obtained.

Production Example 3 115 parts of dimethyl terephthalate, 75 parts of dimethyl inphthalate, 71 parts of ethylene glycol, 110 parts of neopentyl glycol, 0.1 part of zinc 6F acid and 0.1 part of antimony dioxide were charged into a reactor and heated at 140 to 220°C.
The transesterification reaction was carried out over a period of 3 hours. then 2
The polycondensation reaction was carried out at 40 to 270°C under reduced pressure (io to 1 mHg) for 30 minutes. Next, under normal pressure 170-1
Addition reaction was carried out for 30 minutes by adding 615 parts of anhydrous trimelite at 90°C to obtain a polyester resin (A-3) having a molecule of 1t2700, a softening point of 95°C, and a carboxyl group concentration of 41.5 KOHq/l.

Example 3 A biaxially oriented polypropylene film was coated with the same composition and method as in Example 1 except that polyester resin (A-3) was used as the polyester resin, and the performance of the resulting film was evaluated, and good results were obtained. was gotten.

Comparative Example l A mixed aqueous solution of polyester resin (A-1), ethyl cellosolve, and Florard νO-129 contains 1 chit-reaster.
The heat-sealing adhesive was added so that 5% by weight, 6.5% by weight of ethyl cellosolve, and 0.1% by weight of Florador 0-129 were added. This was processed into a biaxially stretched polypropylene film in the same manner as in Example 1, and the performance of the obtained film was evaluated. Transparency, anti-blow. Although the scratchability and moisture resistance were good, similar to those in Examples, the heat seal strength was slightly weaker than in Example 1, and the slip properties were also poor.

Comparative Example 2 A heat seal adhesive was prepared with the same composition as in Example 1 except for Florado FO-129, and an attempt was made to apply it to a biaxially oriented polypropylene film, but there was some repellency. It was not possible to apply it evenly.

Comparative Example 3 The amount of ethyl cellosolve in the composition of Example 1 was 1.5 mm%
The adhesive had the same composition as Example 1 except for #
I tried coating it on a biaxially stretched polypropylene film, but the amount of coating was 1? There was some repellency in areas where the coating was less than 100%.

Claims (1)

[Scope of Claims] 1. (a polyester resin with a molecular weight of 2,500 to 30,000 containing sulfonate 2 and/or salt in the chrysanthemum molecule, (B) acrylate and/or in the molecule A (meth)acrylic acid ester copolymer resin with a Tg of 5 to 105°C containing methacrylate, (0) a water-bathable organic solvent with an I!lft point of 60 to 200°C, ((9) boundary 1. An aqueous solution consisting of a mixture of a killing agent and (E) water, and (A)', (B)
l' (0) + Aqueous polyester yarn i7 where the combination of (D) and (E) satisfies the following formula in Motogaki ratio > solvent. ,,(A)+(B)+(0)+(D)+(E)=!
00 (Shu + (B) = 5 ~ 70 (B) / (A) = , 0.01 ~ 2 (0) = 0 ~ 50, (D) = 0 ~ 10 (Shu = 15 ~ 95