JP6988686B2 - Heat sealant, heat sealable film and packaging material - Google Patents

Description

The present invention relates to a heat-sealing agent, a heat-sealing film using the same, and a packaging material.

In recent years, heat-sealing films obtained by coating a plastic film such as aluminum foil, PET (polyethylene terephthalate), polyamide, and polyolefin with a heat-sealing agent have been used in medical device packaging and food packaging.

Heat-sealable films do not exhibit adhesiveness during storage or distribution in a stacked or rolled state, or during molding, but can only develop adhesiveness when heated (heat-sealed). Desired. Therefore, a thermoplastic resin such as a polyester resin, a vinyl chloride-vinyl acetate copolymer, or an ethylene-vinyl alcohol copolymer is usually used as the heat-sealing resin. Further, a combination of a thermoplastic resin having a reactive group and a curing agent so that these thermoplastic resins can be three-dimensionally crosslinked at the time of heat sealing is also known.

On the other hand, in recent years, a heat-sealing film has been desired for refrigerated foods whose contents cannot be heated to a high temperature, for example, individual packaging materials such as cheese and sausage, and is lower than the conventional heat-sealing temperature, for example, at 80 ° C. There is a demand for a heat-sealing agent capable of heat-sealing.
However, as the heat-sealing temperature is lowered, there is a problem that the blocking property (a phenomenon in which films, sheets, etc. are in close contact with each other and become difficult to separate when they are wound or stacked and stored) and slipperiness are lowered.

As a heat-sealing agent capable of heat-sealing at 80 ° C., a heat-sealing agent in which a solid plasticizer is added to a thermoplastic resin is known (see, for example, paragraph 0014 of Patent Document 1). However, the heat sealant may not have the desired blocking resistance.
On the other hand, in order to improve blocking resistance and slipperiness, there is also an example in which a polyhydric alcohol is used as a raw material for a polyurethane resin (see, for example, paragraph 0029 of Patent Document 2). However, depending on the weight average molecular weight of the raw material used, blocking resistance and slipperiness may not be ensured.

Japanese Unexamined Patent Publication No. 2004-244494 Japanese Unexamined Patent Publication No. 2014-004799

An object of the present invention is to provide a heat-sealing film having excellent low-temperature heat-sealing properties and excellent blocking resistance and slipperiness, and a heat-sealing agent used therein.

The present inventors have found that a heat-sealing agent having a heat-sealing resin component and a specific aliphatic diol component solves the above-mentioned problems.

That is, the present invention provides a heat-sealing agent having a heat-sealing resin component and an aliphatic diol component, wherein the aliphatic diol component contains an aliphatic diol having a secondary hydroxyl group and having 10 or more carbon atoms. do.

The present invention also provides a heat-sealing film in which the above-mentioned heat-sealing agent is provided on a substrate.

The present invention also provides a packaging material using the heat-sealable film described above.

By using the heat-sealing agent of the present invention, it is possible to obtain a heat-sealing film having excellent low-temperature heat-sealing properties and excellent blocking resistance and slipperiness.

(Heat-sealing resin component)
The heat-sealing resin component used in the present invention is not particularly limited, and a known thermoplastic resin used for heat-sealing can be used. Specifically, a thermoplastic resin having a softening temperature of at least 40 ° C. or higher, which does not cause adhesiveness at room temperature or lower, is preferable. Further, a thermoplastic resin having a glass transition temperature of at least −10 ° C. or higher is preferable.
Examples of such thermoplastic resins include polyester resins, vinyl chloride resins, vinyl chloride-vinyl acetate resins, acrylic acid ester resins, styrene-acrylic acid ester resins, styrene-butadiene resins, and butadiene resins. , Vinyl acetate resin, ethylene-vinyl alcohol resin, ethylene-acrylic acid ester resin, ethylene-acrylic acid resin, ethylene-vinyl acetate resin, urethane resin, styrene-isoprene resin and the like.
Of these, polyester resins, vinyl chloride-vinyl acetate resins, acrylic acid ester resins, ethylene-vinyl acetate resins, urethane resins or ethylene-vinyl alcohol resins are preferable.

Further, as the thermoplastic resin, a main agent composed of a thermoplastic resin grafted or pendant with a reactive group such as a hydroxyl group, a glycidyl group or a carboxyl group, an isocyanate curing agent or a polyamine curing agent capable of thermally reacting with the reactive group, etc. Compositions in combination with the curing agent of can also be used. For example, a polyester resin grafted or pendant with a reactive group, a polyether resin grafted or pendant with a reactive group, a polyurethane resin grafted or pendant with a reactive group, or a graft or pendant with a reactive group. Examples thereof include a combination of a main agent such as an epoxy resin or a polyol resin grafted or pendant with a reactive group and a curing agent such as an isocyanate curing agent or a polyamine curing agent.

Specifically, for example, polyols such as polyethylene glycol, acrylic polyols, polyester polyols, polyether polyols, polyester polyether polyols, polyester polyurethane polyols, castor oil, dehydrated castor oil, castor oil, which is a hydrogenated additive of castor oil, Examples thereof include castor oil-based polyols such as an adduct of 5 to 50 mol of alkylene oxide of castor oil.

Examples of the curing agent include polyisocyanates having an aromatic structure in the molecular structure such as tolylene diisocyanate, diphenylmethane diisocyanate, polypeptide diphenylmethane diisocyanate, 1,5-naphthalenediocyanate, triphenylmethane triisocyanate, and xylylene diisocyanate. Compounds in which some of the NCO groups of these polyisocyanates are modified with carbodiimide; alphanate compounds derived from these polyisocyanates; isophorone diisocyanates, 4,4'-methylenebis (cyclohexylisocyanate), 1,3- (isocyanatomethyl) ) Polyisocyanates having an alicyclic structure in the molecular structure such as cyclohexane; linear aliphatic polyisocyanates such as 1,6-hexamethylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, and alphanate compounds thereof; Isocyanurates of polyisocyanates; Allophanates derived from these polyisocyanates; Bullet bodies derived from these polyisocyanates; Trimethylolpropane-modified adducts; Reaction products of the various polyisocyanates described above with polyol components. Polyfunctional isocyanates such as certain polyisocyanates, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, heptaethyleneoctamine, octaethylenenonamine, nonaethylenedecamine, piperazine or carbon. Examples thereof include polyethylene polyamines such as N-aminoalkylpiperazine having an alkyl chain having 2 to 6 atoms, and amine compounds such as 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isocyanolonediamine or IPDA). ..

(Alphatic diol component)
The aliphatic diol component used in the present invention is characterized by containing an aliphatic diol having a secondary hydroxyl group and having 10 or more carbon atoms.
Specifically, 1,10-decanediol, 1,11-undecanediol, 1,12-undecanediol, octadecane-1,12-diol (also known as hydroxystearyl alcohol), 1,2-decanediol, 1,2. -Dodecanediol, 1,2-tetradecanediol, 1,2-heptadecanediol, 1,2-hexadecanediol, 1,2-nonadecandiol, 1,2-octadecanediol and the like can be mentioned. Of these, octadecane-1,12-diol is preferable.

The aliphatic diol component is preferably blended in a ratio of 0.003 to 0.05 with respect to 1 solid content of the heat-sealing resin component, and is preferably in a ratio of 0.01 to 0.025. It is still preferable to blend in.

(Other ingredients)
As the heat sealant of the present invention, additives can be appropriately used as long as the effects of the present invention are not impaired. For example, known organic solvents, solid plasticizers, waxes such as paraffin wax and carnauba wax, antistatic agents, ultraviolet absorbers, polystyrene-based and polymethacrylic acid ester-based organic polymer fine particles, and inorganic fine particles such as silicon dioxide. An anti-blocking agent or the like can be used.

(solvent)
In the present invention, the organic solvent is added to dilute the heat sealant and facilitate coating. Specifically, highly soluble toluene, xylene, methylene chloride, tetrahydrofuran, methanol, ethanol, isopropyl alcohol, methyl acetate, ethyl acetate, n-butyl acetate, acetone, methyl ethyl ketone (MEK), cyclohexanone, toluol, xylol, n- It may be diluted with hexane, cyclohexane or the like. From the viewpoint of solvent regulation in recent years, methanol, ethanol, isopropyl alcohol, methyl acetate, ethyl acetate, n-butyl acetate, acetone, methyl ethyl ketone (MEK), cyclohexanone, toluol, xylol, n-hexane, cyclohexane and the like can be mentioned. Among these, ethyl acetate and methyl ethyl ketone (MEK) are preferably used from the viewpoint of solubility, and ethyl acetate is particularly preferable. Even if only unregulated solvent is used, the solution at low temperature is stable. The amount of the organic solvent used depends on the required viscosity, but is often used in the range of approximately 20 to 80% by mass.

(Solid plasticizer)
As the solid plasticizer used in the present invention, an ester compound having a polarity of being compatible with the thermoplastic resin and softening to improve the adhesiveness is preferably selected. A phthalate ester compound such as dicyclohexylphthalate can also be used, but a benzoic acid ester compound, a hindered phenol ester compound, a fatty acid ester compound and the like are preferably used from the viewpoint of safety and hygiene.

The melting point of the solid plasticizer is preferably 50 to 150 ° C., preferably 50 to 80 ° C., because the blocking resistance is lowered at 50 ° C. or lower and the heat seal temperature tends to be high at 150 ° C. or higher. It is more preferable to have. Further, the molecular weight of the solid plasticizer is preferably in the range of 200 to 1000 from the viewpoint of smoothly melting when heated to soften the thermoplastic resin and further preventing volatilization.

Examples of the benzoic acid ester compound used as a preferable solid plasticizer include benzoic acid sucrose, benzoic acid diethylene glycol ester, benzoic acid glyceride, benzoic acid pentaerythrit ester, benzoic acid trimethylol ethane ester, benzoic acid trimethyl propane ester and the like. ..

Examples of the hindered phenol ester compound used as a preferred solid plasticizer include triethylene glycol bis [3- (3-t-butyl-4-hydroxyphenyl) propionate] and triethylene glycol bis [3- (3-t-butyl) propionate]. -4-Hydroxy-5-methylphenyl) propionate], triethylene glycol bis [3- (3,5-di-t-butyl-4-hydroxy-phenyl) propionate], 1,6-hexanediol bis [3- (3-t-butyl-4-hydroxyphenyl) propionate], 1,6-hexanediol bis [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate], 1,6-hexanediol Bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], thiobis [ethylene 3- (3-t-butyl-4-hydroxyphenyl) propionate], thiobis [ethylene 3- (3) -T-butyl-4-hydroxy-5-methylphenyl) propionate], thiobis [ethylene 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate]. Particularly preferred solid plasticizers include triethylene glycol bis [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate] and 1,6-hexanediol bis [3- (3,5-di). -T-Butyl-4-hydroxyphenyl) propionate], thiobis [ethylene 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate].

Examples of the fatty acid ester compound used as a preferable solid plasticizer include ethylene glycols such as myristic acid, partiminic acid and stearic acid, butandiol, hexanediol, octanediol, esterified products with decanediol, adipic acid, azelaic acid and sebacic acid. There are esters of dibasic acids such as lauryl alcohol and stearyl alcohol.

(Base material)
The base material used in the present invention is not particularly limited, and a known film as used in ordinary packaging materials can be used, but from the viewpoint of easily exhibiting the effects of the present invention, high rigidity is used. It is preferable to use a plastic substrate having high gloss, particularly a biaxially stretched resin film. Further, in the case of applications that do not require transparency, the aluminum foil and the aluminum vapor deposition layer can be used alone or in combination.
Specifically, PET (polyethylene terephthalate), PBT (polybutylene terephthalate), OPP (biaxially stretched polypropylene), aluminum foil, PE (polyethylene), VMPET (aluminum-deposited polyethylene terephthalate), A-PET (acrystalline polyethylene). A film made of terephthalate), paper, PS (polystyrene), nylon, EVOH (ethylene-vinyl alcohol copolymer), or a combination thereof can be used.

(Manufacturing method of heat-sealing film)
The heat-sealing film of the present invention is formed by providing the heat-sealing agent of the present invention on a substrate. The heat sealant of the present invention may be applied as it is on the base material, or a primer layer of one or more layers may be provided between the base material and the heat sealant. There are no particular restrictions on the primer species used.
The coating method can be performed by a known method, for example, a gravure coater, a reverse coater, a kiss coater, an air knife coater, a Mayer bar coater, a roll coater, a dip coater, or the like. Further, the coating can be applied to only one side or both sides of the film depending on the purpose. Furthermore, either offline (coating after film molding) or in-line (coating during film molding) can be used.
Further, a printing ink printed on the substrate by gravure printing or flexographic printing may be used, and even in this case, a good appearance can be exhibited. As the above-mentioned printing ink, a solvent type, a water-based type, or an active energy ray-curable ink can be used.

When the heat-sealing agent used in the present invention is used, the adhesive is cured in 12 to 72 hours at room temperature or under heating after heat-sealing, and practical physical properties are exhibited.
There are no particular restrictions on the drying conditions. The temperature may be any temperature at which a transparent film is formed, and a hot air dryer or the like is usually used, the drying temperature is 50 to 180 ° C. (depending on the coating method), and the drying time is about 1 second to 5 minutes. Further, if necessary, as a post-treatment, a corona discharge treatment or the like may be performed after drying.
The amount of coating is not particularly limited, but 0.5 to 5.0 g / m ² is preferable. If the amount of coating is small, coating film defects will occur and sufficient heat-sealing properties cannot be obtained. On the other hand, if the amount of coating is large, the heat-sealing time and amount of heat will be enormous, and the cost will be reduced. has no effect.

(Packaging material)
Examples of the packaging material using the heat-sealing film of the present invention include packaging bags, containers, lid materials for containers and the like used for foods, chemicals, cosmetics, sanitary, industrial parts, miscellaneous goods, magazines and the like. As specific embodiments, there are various types such as a three-way seal bag, a four-way seal bag, a gusset packaging bag, a pillow packaging bag, a Goebel top type bottomed container, a tetraclassic, a bruck type, a tube container, a paper cup, and a lid material. Further, the package of the present invention may be appropriately provided with an easy-opening process or a resealable means.

The packaging bag is heat-sealed by stacking layers of the heat-sealing agent of the heat-sealing film of the present invention on top of each other, or by superimposing a layering agent of the heat-sealing agent and another base material capable of heat-sealing. Can be obtained by

Hereinafter, the present invention will be specifically described with reference to Examples.

(Examples 1 to 6 and Comparative Examples 1 to 2)
The blending amounts shown in Table 1 were mixed to obtain a heat sealant. By applying the heat sealant to a 30 μ thick hard aluminum foil (manufactured by Toyo Aluminum Co., Ltd.) with a wire bar and drying at 120 ° C. for 60 seconds, the amount of the heat sealant applied is about 5.0 g / m ^2. A heat-sealing film was obtained.

Table 1 shows the evaluation results of the heat seal strength, blocking resistance, and slipperiness of the heat sealable film.

(Judgment method)
(Heat seal strength)
Using a heat-inclined heat seal tester (manufactured by Tester Sangyo Co., Ltd.), the coated surfaces were heat-sealed at a seal temperature of 80 to 180 ° C. (at intervals of 20 ° C.) at a pressure of 1 kg / cm ² and a time of 1 second. The sample width was 15 mm, and the 180 ° peel strength was measured at a tensile speed of 200 mm / min, which was used as the heat seal strength. If it is 1.0N / 15mm or more, it can be regarded as a practical level.

(Blocking resistance)
The coated / coated surface (hereinafter, F / F) or coated / uncoated surface (hereinafter, F / B) of the test piece cut into 4 cm squares are overlapped, and a load of 5 kg is applied at 40 ° C., and the test piece is static for 24 hours. I put it. After returning to room temperature, the state of the coating film at the time of peeling the test piece, the tearing method of the base film, and the like were visually evaluated on a 5-point scale.
5: Easy peeling.
4: Can be peeled off, and there is a crisp sound when peeling off.
3: Can be peeled off, and there are traces on the coating film after peeling.
2: Difficult to peel off, no substrate destruction.
1: Difficult to peel off, with substrate destruction.

(Slippery)
The coated / coated surface (hereinafter, F / F) or coated / uncoated surface (hereinafter, F / B) of the test piece cut into 8 cm squares are overlapped, and a load of 200 g is applied at room temperature, and the coefficient of static friction and dynamic friction are applied. The coefficient was measured. If both the coefficient of static friction and the coefficient of dynamic friction are 0.70 or less, it can be said that the slipperiness is excellent.

(Stability over time)
The state after storing the heat sealant mixed in the blending amounts shown in Table 1 in an environment of 4 ° C. for 1 week was evaluated.
〇: No precipitate ×: With precipitate

In Table 1, the abbreviations are as follows.
VINNOL H15 / 45M (Wacker): Vinyl chloride-vinyl acetate resin Pandex TR-02 (DIC): Urethane resin Degalan P-24 (Ebonic): Acrylic resin Elitel UE-3240 (Unitica) Made by: Polyester resin Byron 500 (manufactured by Toyo Spinning Co., Ltd.): Polyester based resin Byron GK-880 (manufactured by Toyo Spinning Co., Ltd.): Polyester resin Takenate D-110N (manufactured by Mitsui Chemicals Co., Ltd.): Solvent-containing isocyanate-terminated urethane resin

From the above results, Examples 1 to 6 had good blocking resistance and slipperiness while maintaining the low temperature sealing property. That is, it can be said that by using the polyhydric alcohol of the present invention as a lubricant, excellent blocking resistance and slipperiness can be exhibited while ensuring low temperature heat sealing property. In addition, the solution is excellent in low temperature stability. On the other hand, Comparative Examples 1 and 2 have a composition that does not contain a polyhydric alcohol as a lubricant, and are inferior in blocking resistance and slipperiness.

Claims (6)

A heat-sealing agent having a heat-sealing resin component and an aliphatic diol component, wherein the aliphatic diol component contains an aliphatic diol having a secondary hydroxyl group and having 10 or more carbon atoms. The heat-sealing agent according to claim 1, wherein the heat-sealing resin component is a polyester-based resin, a vinyl chloride-vinyl acetate-based resin, a urethane-based resin, or an ethylene-vinyl alcohol-based resin. The heat sealant according to claim 1 or 2, which contains a curing agent. The heat sealant according to claim 1 or 2, wherein the aliphatic diol having a secondary hydroxyl group and having 10 or more carbon atoms is octadecane-1,12-diol. A heat-sealing film comprising the heat-sealing agent according to any one of claims 1 to 4 provided on a substrate. A packaging material using the heat-sealing film according to claim 5.