JP3529552B2 - Hot melt adhesive composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hot melt adhesive composition having excellent adhesive strength and having little deterioration with time of the adhesive strength.

[0002]

2. Description of the Related Art Hot melt adhesive compositions have the following properties: flowability by heating and melting, fast set time, solventless type, no toxicity, etc. There are advantages. And with these advantages, binding back binding, cardboard and carton sealing,
In recent years, the amount of use thereof has increased in various fields such as bag making, carpentry, and shoe making, and in particular, it has become extremely popular in the field of paper sealing and packaging.

The above packaging field includes the field of food packaging and the like, and in the field of food packaging, hot melt adhesion using polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, etc. as a base resin. Agents are widely used. However, in a package pair formed using a hot melt adhesive having the above base resin,
Soybean oil, sesame oil, cottonseed oil, rapeseed oil, olive oil, peanut oil, coconut oil and other vegetable oils, whale oil, beef tallow, animal oils such as lard, and so-called edible oils (hereinafter simply edible oils) to be eaten Foods seasoned with oil) and preserved and processed,
When packaging and storing food mixed with edible oil, there is a problem that adhesion of bags and containers, adhesive composition of sealing part is attacked by edible oil and cracked or adhesiveness is deteriorated. It was

Therefore, the object of the present invention is to provide excellent adhesiveness,
A further object of the present invention is to provide a hot-melt adhesive composition, which is used in forming a packaging material for packaging foods containing edible oil and the like, and whose adhesiveness is less likely to deteriorate with time.

[0005]

SUMMARY OF THE INVENTION The present invention is a cyclopenta
20-50% by weight of an ethylene-α-olefin copolymer copolymerized by using a dienyl complex as a catalyst and having a density of 0.90 g / cm ³ or less, as a tackifying resin
A hot melt adhesive composition containing 5 to 70% by weight of a hydrogenated petroleum resin and 5 to 45% by weight of a softening agent , which is for producing a packaging container for foods containing edible oil. By providing it, the said objective was achieved.

The present invention also provides the above hot melt adhesive composition, wherein the content of the tackifying resin is 15 to 50% by weight. The present invention also provides the hot melt adhesive composition in which the softening agent contains process oil. Further, the present invention, the softening agent is to provide the hot melt adhesive composition containing a melting point 40 to 70 ° C. paraffin wax.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The hot melt adhesive composition of the present invention will be described in more detail below. The hot melt adhesive composition of the present invention contains a specific ethylene-α / olefin copolymer, a tackifying resin and a softening agent at specific contents.

The above-mentioned specific ethylene-α-olefin copolymer used in the present invention has a density of 0.9.
0 g / cm ³ or less, preferably 0.880 to 0.860
It is an ethylene-α-olefin copolymer having a g / cm ³ . If the density exceeds 0.90 g / cm ³ , the melt viscosity of the hot melt adhesive becomes too high. Here, the above-mentioned density is measured in the same manner as a commonly known polymer density measurement.

[0009] As the ethylene-.alpha. · olefin copolymer satisfies the above density, the ethylene-.alpha. · olefin copolymer comprising a cyclopentadienyl complexes are copolymerized using as a catalyst is used.

In the above ethylene-α-olefin copolymer, the α-olefin copolymerized with ethylene is an α-olefin having 3 to 30 carbon atoms, specifically, for example, propylene, 1-butene, 1- Pentene, 1-hexene, 1-octene, 1-heptene, 4-methylpentene-1,4-methylhexene-1,4,4-dimethylpentene-1, octadecene and the like can be mentioned. Among these, 1-hexene, 1-octene, 1-heptene, 4
-Methyl-pentene-1 is preferably used.

Further, in the ethylene-α-olefin copolymer, the cyclopentadienyl complex used as a catalyst when copolymerizing ethylene and α-olefin is a compound represented by the following formula (I): Etc.

ML _X (I) [wherein, M represents a transition metal selected from the group consisting of Zr, Ti, Hf, V, Nb, Ta and Cr, and L represents
A ligand having a cyclopentadienyl skeleton, which is a ligand coordinated to the transition metal, a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryl group having 1 to 12 carbon atoms.
Roxy group, C1-C12 trialkylsilyl group, S
O ₃ R group (where R is a hydrocarbon group having 1 to 8 carbon atoms which may have a substituent such as halogen), a halogen atom or a hydrogen atom, and x is the same as the valence of the above transition metal. Is. However, when a plurality of Ls are coordinated, they may be different groups, but at least one is a group having a cyclopentadienyl skeleton. That is,
When x is 1, L is a group having a cyclopentadienyl skeleton, and when x is 2 or more, at least one of a plurality of L is a cyclopentadienyl skeleton. Is a group having ]

Examples of the group having a cyclopentadienyl skeleton include cyclopentadienyl group, methylcyclopentadienyl group, dimethylcyclopentadienyl group, trimethylcyclopentadienyl group and tetramethylcyclopentadienyl group. Enyl group, pentamethylcyclopentadienyl group, ethylcyclopentadienyl group, methylethylcyclopentadienyl group, propylcyclopentadienyl group, methylpropylcyclopentadienyl group,
Alkyl-substituted cyclopentadienyl groups such as butylcyclopentadienyl group, methylbutylcyclopentadienyl group, hexylcyclopentadienyl group; or indenyl group, 4,5,6,7-tetrahydroindenyl group, fluorenyl A group etc. can be illustrated. Further, these groups may be substituted with a halogen atom, a trialkylsilyl group or the like.

As the group having a cyclopentadienyl skeleton, an alkyl-substituted cyclopentadienyl group is particularly preferable among the above-exemplified groups.

When the compound represented by the general formula (I) contains two or more groups having a cyclopentadienyl skeleton, the two groups having a cyclopentadienyl skeleton among them are: It may be bonded via an alkylene group such as ethylene and propylene; a substituted alkylene group such as isopropylidene and diphenylmethylene; a silylene group or a substituted silylene group such as a dimethylsilylene group, a diphenylsilylene group, and a methylphenylsilylene group.

Examples of the hydrocarbon group having 1 to 12 carbon atoms include an alkyl group, a cycloalkyl group, an aryl group and an aralkyl group. More specifically, the alkyl group is a methyl group, Ethyl group, propyl group,
Examples include isopropyl group and butyl group, examples of cycloalkyl group include cyclopentyl group and cyclohexyl group, examples of aryl group include phenyl group and tolyl group, and examples of aralkyl group include benzyl group and neophyll group. Examples include groups. Examples of the alkoxy group include methoxy group, ethoxy group, butoxy group, etc., examples of the aryloxy group include phenoxy group, etc., and examples of the halogen atom include fluorine, chlorine, bromine, iodine and the like.

Examples of the SO ₃ R group include p-toluenesulfonato group, methanesulfonato group, trifluoromethanesulfonato group and the like.

The compound containing a group having such a cyclopentadienyl skeleton is more specifically represented by the following formula (II) when the valence of the transition metal is 4.

R ² _k R ³ _l R ⁴ _m R ⁵ _n M (II) [wherein, M is the above transition metal, and R ² is a group having a cyclopentadienyl skeleton (ligand ), And R ³ , R
⁴ and R ⁵ are each a group having a cyclopentadienyl skeleton, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a trialkylsilyl group, a SO ₃ R group, a halogen atom or a hydrogen atom. Where k is an integer greater than or equal to 1, and k + 1 + m
+ N = 4. ]

In the present invention, in the above formula (II), R
^A compound in which at least two of ² , R ³ , R ⁴ and R ⁵ , for example, R ² and R ³ are groups (ligands) having a cyclopentadienyl skeleton is preferably used. The skeleton-bearing groups (eg R ² and R ³ ) may be attached as described above.

Specific examples of the above compounds in which M is zirconium are shown below. Bis (indenyl) zirconium dichloride, bis (indenyl) zirconium dibromide, bis (indenyl) zirconium bis (p-toluenesulfonato) bis4,5,6,7-
Tetrahydroindenyl) zirconium dichloride, bis (fluorenyl) zirconium dichloride, ethylenebis (indenyl) zirconium dichloride, ethylenebis (indenyl) zirconium dibromide, ethylenebis (indenyl) dimethylzirconium, ethylenebis (indenyl) diphenylzirconium, ethylenebis ( Indenyl) methyl zirconium monochloride, ethylene bis (indenyl) zirconium bis (methane sulfonate), ethylene bis (indenyl) zirconium bis (p-toluene sulfonate), ethylene bis (indenyl) zirconium bis (trifluoromethane sulfonate), ethylene Bis (4,5,6,7-tetrahydroindenyl) zirconium dichloride, isopropylidene (cyclopenta Enyl - fluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl - methylcyclopentadienyl) zirconium dichloride, dimethylsilylene bis (cyclopentadienyl)
Zirconium dichloride, dimethylsilylene bis (methylcyclopentadienyl) Zirconium dichloride, dimethylsilylene bis (dimethylcyclopentadienyl)
Zirconium dichloride, dimethyl silylene bis (trimethylcyclopentadienyl) zirconium dichloride, dimethyl silylene bis (indenyl) zirconium dichloride, dimethyl silylene bis (indenyl) zirconium bis (trifluoromethane sulfonate), dimethyl silylene bis (4,5,6,6) 7-Tetrahydroindenyl) zirconium dichloride, dimethylsilylenebis (cyclopentadienyl-fluorenyl) zirconium dichloride, diphenylsilylenebis (indenyl)
Zirconium dichloride, methylphenylsilylene bis (indenyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dibromide, bis (cyclopentadienyl) methylzirconium monochloride, bis (cyclopentadiene) Dienyl) ethyl zirconium monochloride, bis (cyclopentadienyl) cyclohexyl zirconium monochloride, bis (cyclopentadienyl) phenyl zirconium monochloride, bis (cyclopentadienyl) benzyl zirconium monochloride, bis (cyclopentadienyl) ) Zirconium monochloride monohydride, bis (cyclopentadienyl) methyl zirconium monohydride, bis (cyclopentadienyl) Methylzirconium, bis (cyclopentadienyl) diphenylzirconium, bis (cyclopentadienyl) dibenzylzirconium, bis (cyclopentadienyl) zirconium methoxychloride, bis (cyclopentadienyl) zirconium ethoxy chloride, bis (cyclopentapenta Dienyl) zirconium bis (methanesulfonato), bis (cyclopentadienyl) zirconium bis (p-toluenesulfonato), bis (cyclopentadienyl) zirconium bis (trifluoromethanesulfonato), bis (methylcyclopentadiene) (Enyl) zirconium dichloride, bis (dimethylcyclopentadienyl) zirconium dichloride, bis (dimethylcyclopentadienyl) zirconium ethoxy chloride, bis (dimethylcyclopente) Dienyl) zirconium bis (trifluoromethanesulfonato), bis (ethylcyclopentadienyl) zirconium dichloride, bis (methylethylcyclopentadienyl) zirconium dichloride, bis (propylcyclopentadienyl) zirconium dichloride, bis (methylpropylcyclo) Pentadienyl) zirconium dichloride, bis (butylcyclopentadienyl) zirconium dichloride, bis (methylbutylcyclopentadienyl) zirconium dichloride, bis (methylbutylcyclopentadienyl) zirconium bis (methanesulfonate), bis (trimethyl) Cyclopentadienyl) zirconium dichloride, bis (tetramethylcyclopentadienyl) zirconium dichloride, bis (pentamethylcyclopentadiene (Enyl) zirconium dichloride, bis (hexylcyclopentadienyl) zirconium dichloride, bis (trimethylsilylcyclopentadienyl)
Zirconium dichloride.

In the above-exemplified compounds, disubstituted cyclopentadienyl rings such as dimethylcyclopentadienyl include 1,2- and 1,3-substituted compounds,
Trisubstituted compounds such as dimethylcyclopentadienyl are 1, 2,
Includes 3- and 1,2,4-substitutes. Also propyl,
Alkyl groups such as butyl are n-, i-, sec-, te
Including isomers such as rt-. Further, examples of the compound include a cyclopentadienyl complex in which zirconium is replaced with titanium, hafnium, vanadium, niobium, tantalum, or chromium in the above compound in which M is zirconium.

Further, the cyclopentadienyl complex is
When used, they can be used alone or as a mixture. Further, it may be diluted with a hydrocarbon or a halogenated hydrocarbon before use. Particularly, in the present invention, a zirconocene compound having a central metal atom of zirconium and a ligand having a group having at least two cyclopentadienyl skeletons is preferably used as the cyclopentadienyl complex.

Further, the cyclopentadienyl complex is
It can also be used in combination with a usual aluminoxane compound or a compound which reacts with the cyclopentadienyl complex to form a stable anion.

The cyclopentadienyl complex catalyst used in the present invention is described in JP-A-4-253711.
Japanese Unexamined Patent Publication (Kokai) No. 4-279592 and Japanese Patent Publication No. 6-50358.
No. 5, JP-A No. 3-188092, or JP-A No.
The polymerization catalyst described in JP-A-84407 can also be used.

The mixing ratio of ethylene and α-olefin in the ethylene-α-olefin copolymer is preferably 40 to 98% by weight of ethylene and 60 to 2% by weight of α.olefin.

The above ethylene-α-olefin copolymer is obtained by mixing ethylene and α-olefin in the presence of a cyclopentadiene complex in an amount of 100 to 3,000 kg / c.
m ² , preferably 300 to 2,000 kg / cm ² , 1
It can be produced by polymerizing by a high pressure ionic polymerization method at a temperature of 25 to 250 ° C., preferably 150 to 200 ° C. In particular, in order to polymerize the cyclopentadienyl complex and the aluminoxane compound in combination, the method described in JP-A-6-61 is disclosed.
No. 1-130314, No. 60-35006,
Stable anions according to the methods described in JP-A-58-19309, JP-A-60-35008, JP-A-3-163088, etc., and by reacting with the cyclopentadienyl complex and the cyclopentadienyl complex. In order to polymerize the compound forming the compound in combination, European Patent No. 277,004, International Publication WO92 / 0172
Polymerization can be carried out according to the high-pressure ionic polymerization method described in JP-A No.

In addition, the MFR of the above ethylene-α / olefin copolymer (JIS K-7210; 190 ° C., 2.
16 kg load) is preferably 0.5 to 500 g
/ 10 minutes.

The ethylene-α-olefin copolymer has a permanent strain of preferably 50% or less, more preferably 0 to 30%, and a hysteresis ratio of 5.0 or less, more preferably 1 or less. It is desirable that it is 0.0 to 3.5. On the other hand, when the permanent strain is 50% or the hysteresis ratio exceeds 5.0, the melt viscosity of the hot melt adhesive becomes too high, which is not preferable.

The permanent set and the hysteresis ratio are
Each is measured as follows. Measuring method of permanent strain: Similar to the measuring method of the hysteresis ratio described below, the length of the sample when the sample was stretched 100% and the initial chuck distance was measured, and the initial length when stretched 100% The ratio (%) of the length that cannot be relaxed (the length of the portion that was elongated and lengthened from the initial length) to the initial length (distance between chucks) was determined, and this was taken as the permanent set. Hysteresis ratio measurement method; to check the elasticity of each sample,
The hysteresis ratio was measured using an elongation tester with an integrating device. That is, a sample having a width of 25 mm was prepared by the elastic member, and the sample was placed in the testing machine with a chuck distance of 100 m.
m so that each sample is 300 mm /
Stretching 100% at a speed of min to create a stretching curve, and then loosening at the same speed to reduce the gap between chucks to 10% of the initial length.
Relaxation was stopped at 0 mm to create a relaxation curve, the areas under the stretching curve and the relaxation curve were measured, and these were substituted into the following equation to calculate the hysteresis ratio. Hysteresis ratio = area under stretch curve / area under relaxation curve

Further, as the above ethylene-α / olefin copolymer, a copolymer obtained by using a known metallocene catalyst may be used.

Further, since the above-mentioned tackifying resin used in the present invention, odor is not like, it is advantageous in the case of using the hot melt adhesive compositions of the present invention for the packaging container producing food, the hydrogenated petroleum resin is needed use.

As the softening agent used in the present invention, process oil, paraffin wax having a melting point of 40 to 70 ° C. (preferably 50 to 60 ° C.) and the like are preferably mentioned. Can be used. That is, the softening agent preferably contains process oil or paraffin wax having the above melting point. As the paraffin wax having the above-mentioned melting point, specifically, a mixture of linear hydrocarbons having 16 to 49 carbon atoms, particularly 20 to 35 carbon atoms is mainly used, and isoparaffin having 16 to 49 carbon atoms, particularly 20 to 35 carbon atoms is used. And those containing a small amount of cycloparaffin. If the melting point of the paraffin wax exceeds the above upper limit, the hot-melt composition obtained will have insufficient oil resistance for corrosion, and if it is less than the above lower limit, the heat resistance may be insufficient. When using, paraffin wax having a melting point within the above range is preferably used. Further, in the present invention,
As the softening agent, a mixture of the process oil and paraffin wax having a melting point within the above range can be preferably used. The mixing ratio of the process oil and the paraffin wax at this time is not particularly limited and is arbitrary, but in order to suppress the stickiness while reducing the melt viscosity of the obtained hot melt adhesive composition,
It is preferable to increase the mixing ratio of the paraffin wax, and it is preferable to increase the mixing ratio of the process oil in order to obtain a sticky feeling while lowering the melt viscosity. That is, by appropriately adjusting the mixing ratio of the process oil and the paraffin wax, it is possible to control the stickiness while lowering the melt viscosity.

The above ethylene-α / olefin copolymer,
The above-mentioned specific contents of the tackifying resin and the softening agent are such that the ethylene-α-olefin copolymer is 20
-50% by weight, preferably 20-40% by weight, and the tackifying resin is 5-70% by weight, preferably 15-5%.
It is 0% by weight, and the softening agent is 5 to 45% by weight, preferably 25 to 45% by weight. When the content of the ethylene-α / olefin copolymer is less than 20% by weight,
The obtained hot-melt adhesive composition has a low cohesive force and low adhesiveness. When it exceeds 50% by weight, the cohesive force becomes too large and the tack force and the adhesive force decrease. Also,
The tackifying resin is considered to give tackiness during melt coating to the hot melt adhesive composition and also to give an adhesive force to the surface of an adherend, but the content of the tackifying resin is 5% by weight. If it is less than%, such an effect is not exhibited, and if it exceeds 70% by weight, the cohesive region of the entire hot melt adhesive composition is reduced and the adhesive strength is reduced. Further, if the content of the paraffin wax is less than 5% by weight, the melt viscosity of the hot-melt adhesive composition does not sufficiently decrease, resulting in poor workability in bonding, and if it exceeds 45% by weight, the adhesive strength decreases. To do.

The hot melt adhesive composition of the present invention may be composed of only the above-mentioned ethylene-α-olefin copolymer, the above tackifying resin and the above softening agent. Other components such as substances usually used as a component, for example, phenol-based, amine-based antioxidants; other components such as plasticizers; fillers such as calcium carbonate and titanium oxide. When these other components are used, their content is preferably 5 to 55% by weight.

The hot-melt adhesive composition of the present invention is formed by mixing the above-mentioned components in a melt-stirring mixer or an extruder to form a linear or pellet form, or kneading with a kneader to form a sheet form. Then, it can be used.

As described above, the hot-melt adhesive composition of the present invention specifies the ethylene-α-olefin copolymer, the tackifying resin, and the softening agent such as paraffin wax, respectively. Since it is contained at the content of
Excellent adhesion performance, and also excellent oil resistance for corrosion. Accordingly, the hot melt adhesive composition of the present invention is suitable as a bonding agent for the packaging container manufacturing of food products such as foods, with edible oil. In particular, when a hydrogenated petroleum resin is used as the tackifying resin, it has no odor, and therefore, in combination with the oil resistance for corrosion,
It is suitable as an adhesive for producing a packaging container or a storage container for food containing edible oil or food mixed with edible oil.

[0038]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The methods for measuring each physical property in the examples are as follows. Unless otherwise specified, "part" and "%" represent "part by weight" and "% by weight", respectively. (1) Oil resistance for corrosion: Two pieces of cardboard, which were previously bent into a semicircular cross section, were overlapped with one edge 5 mm each, and the adhesive composition was applied to the overlapped parts with a width of 10 mm. Applied. Further, the same treatment was applied to the other edge portion to obtain a cylindrical sample having a diameter of about 25 mm. This sample was placed on the insole of a desiccator containing soybean oil at the bottom and left at 50 ° C. for 1 week. After being left for one week, the case where there was no abnormality in the coating on the above-mentioned coated part was marked with ◯, and the case where cracking occurred was marked with x. (2) Adhesion peeling strength: 40 μm aluminum foils were bonded together using the obtained composition, and the tensile speed was 100 m at 20 ° C.
The 180 ° peel adhesive strength was measured under the condition of m / min, and this was taken as the adhesive peel strength. (3) Softening temperature: measured according to JIS-K2531.

Examples 1 to 4 The ethylene-α-olefin copolymer (density 0.865 g / cm ³ , melt index 400 g / 10 min) shown in Table 1 and tackifying resin (hydrogenated petroleum resin, [Table 1]
The softening agent shown in 1 was added and melt-mixed to obtain a hot-melt adhesive composition. Their compositions and their physical properties are shown in [Table 1].

[0041]

[Table 1]

[0042]

The hot melt adhesive composition of the present invention comprises:
It has excellent adhesiveness and, even when it is used for forming a packaging material for packaging foods containing edible oil or the like, the adhesiveness does not decrease with time.

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Claims (4)

(57) [Claims] 1. A cyclopentadienyl complex as a catalyst
Used copolymerizing allowed to become density 0.90 g / cm ³ or less is an ethylene-.alpha. · olefin copolymer 20 to 50% by weight, tackifier 5-70 wt% hydrogenated petroleum resin as the resin and softeners Food containing 5 to 45% by weight and containing edible oil
A hot-melt adhesive composition for producing a packaging container for a product. 2. The content of the tackifying resin is 15-5.
The hot melt adhesive composition according to claim 1, which is 0% by weight. 3. The hot melt adhesive composition according to claim 1, wherein the softening agent contains a process oil. 4. The hot melt adhesive composition according to claim 1, wherein the softening agent contains paraffin wax having a melting point of 40 to 70 ° C.