WO2019171709A1

WO2019171709A1 - Polyolefin-based adhesive composition

Info

Publication number: WO2019171709A1
Application number: PCT/JP2018/047156
Authority: WO
Inventors: 木津本　博俊; 祥平岡野
Original assignee: 東洋紡株式会社
Priority date: 2018-03-06
Filing date: 2018-12-21
Publication date: 2019-09-12
Also published as: TW201938739A; TWI848935B; JPWO2019171709A1; JP7342851B2

Abstract

[Problem] To provide an adhesive composition which can be applied even by low-temperature drying, exhibits satisfactory water resistance and adhesiveness to olefinic resin bases such as polyethylene and polypropylene, and has satisfactory storage stability. [Solution] An adhesive composition which comprises an acid-modified polyolefin (A), a tackifier (B), and an organic solvent (C), wherein the tackifier (B) is a styrene-modified terpene resin.

Description

Polyolefin adhesive composition

The present invention relates to an adhesive composition that exhibits good adhesion performance to olefin-based resin substrates such as polyethylene and polypropylene.

For a long time, research has been conducted on techniques for bonding substrates with low surface energy such as polyethylene and polypropylene, and it is known that it is not easy to design adhesives having high adhesion performance to these materials. As a technique to develop good adhesion to these low surface energy base materials, a technique is proposed in which the surface of the adherend is pretreated by corona discharge or plasma treatment in advance, and the surface energy is increased before bonding. Has been. While these techniques are effective techniques, they require expensive equipment and increase power consumption.

On the other hand, products using olefinic materials such as polyethylene and polypropylene tend to increase more and more in recent years from household items around us to various industrial uses. In particular, for automotive applications, mounting of molding materials made of polypropylene has been actively promoted due to the trend of weight reduction of automobiles. Due to such circumstances, in recent years, more effective adhesives that have not been conventionally developed have been developed. Specific examples can be seen in Patent Documents 1 to 6.

JP 2012-197388 A JP 2013-95873 A Japanese Patent Laid-Open No. 2005-220153 JP 2001-152119 A JP 2002-146315 A JP 2009-235289 A

Patent Documents 1 and 2 are examples of moisture-curing adhesives, and are not suitable for film adhesion or coating agents. Patent Documents 3 to 6 are all water-based adhesives, but the emulsifier contained in the adhesive and the wetting agent used in coating cause bleeding out, resulting in a decrease in adhesiveness and a problem with water resistance. In some cases, and since it is water-based, high temperature heating is required to dry the adhesive, and thus it may not be applicable to a substrate having a low softening point such as polyethylene.

In order to solve the above problems, the present invention can be applied at a low temperature (80 ° C.), and exhibits good adhesion performance and water resistance to olefin-based tree substrates such as polyethylene and polypropylene. And it aims at providing the adhesive composition with favorable storage stability.

In order to achieve the above-mentioned problems, the present inventors have intensively studied and found that an adhesive composition containing an acid-modified polyolefin, a tackifier and an organic solvent is effective in solving the above problems, and proposes the following inventions. It came to. That is, this invention consists of the following structures.

An adhesive composition containing an acid-modified polyolefin (A), a tackifier (B), and an organic solvent (C), wherein the tackifier (B) is a styrene-modified terpene resin. object. *

The acid value of the acid-modified polyolefin (A) is preferably 2 to 50 mgKOH / g, and the melting point is preferably 50 to 95 ° C. The acid-modified polyolefin (A) preferably contains propylene and 1-butene as olefin components, and the molar ratio of propylene to 1-butene is propylene / 1-butene = 98 to 60/2 to 40.

The tackifier (B) is preferably in the range of 5 to 80 parts by mass with respect to 100 parts by mass of the acid-modified polypropylene (A).

The organic solvent (C) preferably contains a hydrocarbon solvent (C1) and a polar solvent (C2) comprising an ester solvent and / or a ketone solvent, and further contains an alcohol solvent (C3). It is more preferable.

Any of the above-mentioned adhesive compositions used for adhesion of a polyethylene substrate, and a laminate of polyethylene substrates bonded using the adhesive composition.

The adhesive composition of the present invention has good storage stability, is excellent in adhesion and water resistance to low surface energy substrates such as polyolefin resins, and is useful for adhesion of substrates such as polyethylene. . Moreover, it is suitable also as adhesion | attachment and coating agents, such as a film and a label.

Hereinafter, embodiments of the present invention will be described in detail.

<Acid-modified polyolefin (A)>
The acid-modified polyolefin (A) used in the present invention is not limited, but at least one of polyethylene, polypropylene, and propylene / α-olefin copolymer includes at least one of α, β-unsaturated carboxylic acid and acid anhydride thereof. What is obtained by grafting 1 type is preferable.

The propylene / α-olefin copolymer is obtained by copolymerizing α-olefin with propylene as a main component. As the α-olefin, for example, ethylene, 1-butene, 1-heptene, 1-octene, 4-methyl-1-pentene, vinyl acetate, or the like can be used. Among these α-olefins, ethylene and 1-butene are preferable, and 1-butene is most preferable.

Examples of at least one of α, β-unsaturated carboxylic acid and acid anhydrides thereof include maleic acid, itaconic acid, citraconic acid, and acid anhydrides thereof. Among these, acid anhydrides are preferable, and maleic anhydride is more preferable. Specifically, maleic anhydride-modified polypropylene, maleic anhydride-modified propylene / ethylene copolymer, maleic anhydride-modified propylene / 1-butene copolymer, maleic anhydride-modified propylene / ethylene / 1-butene copolymer, etc. These acid-modified polyolefins can be used alone or in combination of two or more. Of these, maleic anhydride-modified propylene / 1-butene copolymer is preferred.

The acid value of the acid-modified polyolefin (A) is preferably in the range of 2 to 50 mgKOH / g from the viewpoint of adhesion to the polyolefin resin substrate and compatibility with the tackifier (B). The range is more preferably 3 to 40 mgKOH / g, still more preferably 5 to 30 mgKOH / g, and particularly preferably 7 to 25 mgKOH / g.

The melting point (Tm) of the acid-modified polyolefin (A) is preferably in the range of 50 ° C to 95 ° C. More preferably, it is in the range of 55 ° C to 80 ° C, and most preferably in the range of 60 ° C to 75 ° C. If it is less than the above value, the cohesive force derived from crystals becomes weak, and the adhesiveness and chemical resistance may be inferior. On the other hand, when the above value is exceeded, the solution stability and fluidity are low, and there may be a problem in operability when bonding.

The acid-modified polyolefin (A) preferably has propylene and 1-butene as olefin components. A preferred range of the molar ratio of propylene to 1-butene is propylene / 1-butene = 98 to 60/2 to 40, and more preferably 90 to 70/10 to 30. When the molar ratio of propylene is 60% or more, excellent adhesiveness with a polyolefin substrate can be expressed. Further, when the molar ratio of 1-butene is 2% or more, the solubility in an organic solvent is increased, and the coating property as an adhesive is improved.

As the olefin component, the total amount of propylene and 1-butene component is preferably 62 mol% or more. More preferably, it is 80 mol% or more, More preferably, it is 90 mol% or more, Especially preferably, it is 95 mol% or more, and it may be 100 mol%. If it is less than the above value, the adhesion and chemical resistance may decrease.

The weight average molecular weight (Mw) of the acid-modified polyolefin (A) is preferably in the range of 10,000 to 200,000. More preferably, it is in the range of 20,000 to 180,000, more preferably in the range of 30,000 to 160,000, particularly preferably in the range of 40,000 to 140,000, and most preferably 50 , 110,000 to 110,000. If it is less than the above value, the cohesive force becomes weak and the adhesiveness may be inferior. On the other hand, when the above value is exceeded, there may be a problem in operability when bonding due to low fluidity, and the compatibility with the tackifier (B) may be poor.

The method for producing the acid-modified polyolefin (A) is not particularly limited, and for example, radical graft reaction (that is, generating radical species for the polymer to be the main chain, and using the radical species as a polymerization initiation point, the unsaturated carboxylic acid and Reaction for graft polymerization of an acid anhydride).

Although it does not specifically limit as a radical generator, It is preferable to use an organic peroxide. The organic peroxide is not particularly limited, but di-tert-butyl peroxyphthalate, tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy- Peroxides such as 2-ethylhexanoate, tert-butyl peroxypivalate, methyl ethyl ketone peroxide, di-tert-butyl peroxide, lauroyl peroxide; azobisisobutyronitrile, azobisisopropionitrile, etc. Examples thereof include azonitriles.

<Tackifier (B)>
The tackifier (B) used in the present invention needs to be a styrene-modified terpene resin. The styrene-modified terpene resin is preferably a copolymer resin of a styrene monomer and a terpene monomer. When the tackifier (B) is a styrene-modified terpene resin, the adhesiveness, water resistance and chemical resistance of the adhesive composition are improved.

Examples of the styrene monomer include styrene, alkyl styrene, aryl styrene, halogenated styrene, alkoxy styrene, vinyl benzoate and the like. Examples of the alkyl styrene include o-methyl styrene, m-methyl styrene, p-methyl styrene, o-ethyl styrene, m-ethyl styrene, p-ethyl styrene, on-propyl styrene, mn-propyl styrene, p -N-propyl styrene, o-isopropyl styrene, m-isopropyl styrene, p-isopropyl styrene, mn-butyl styrene, pn-butyl styrene, p-tert-butyl styrene, 4-butenyl styrene, 2, Examples include 4-dimethylstyrene, 2,5-dimethylstyrene, 3,5-dimethylstyrene, mesitylstyrene, and the like. Examples of the aryl styrene include p-phenyl styrene. As halogenated styrene, o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, o-bromostyrene, m-bromostyrene, p-bromostyrene And o-methyl-p-fluorostyrene. Examples of alkoxystyrene include o-methoxystyrene, m-methoxystyrene, p-methoxystyrene and the like. Of these, styrene is particularly preferred. The styrene monomer may be used alone or in combination of two or more.

The styrene-modified terpene resin is preferably a resin represented by the structure of the general formula (1).

In the general formula (1), R is hydrogen, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, halogen (fluorine, chlorine, bromine, iodine), or an alkoxy group having 1 to 10 carbon atoms. Preferably, it is preferably hydrogen. m is preferably an integer of 1 to 10, more preferably 2 to 8, and still more preferably 3 to 5. n is preferably an integer of 1 to 10, more preferably 2 to 8, and still more preferably 3 to 5.

It is desired that the styrene-modified terpene resin used for the tackifier (B) has high compatibility with the acid-modified polyolefin (A). Due to the high compatibility with the acid-modified polyolefin, excellent adhesion is exhibited. Examples of the method for confirming compatibility include a method for confirming the transparency of a dried coating film prepared by mixing the acid-modified polyolefin (A) and the tackifier (B). The higher the transparency, the higher the compatibility. It is judged. The transparency can be confirmed visually, but more accurately can be determined by using a HAZE meter (preferably 1.0 or less, more preferably 0.5 or less). Or the dynamic viscoelastic property of the produced dry film is measured, and if the main dispersion peak of the loss elastic modulus (E ″) is not broad compared with that before the tackifier (B) is blended, the compatibility is good. To be judged.

The content of the tackifier (B) in the adhesive composition of the present invention is preferably in the range of 5 to 80 parts by mass, more preferably 8 to 60 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin (A). More preferably, it is 10 to 50 parts by mass, and most preferably 20 to 40 parts by mass. If it is less than the above value, the adhesion to the polyolefin substrate may be inferior. On the other hand, when the above value is exceeded, the cohesive strength of the acid-modified polyolefin (A) may be inhibited, and the adhesive strength and chemical resistance may be lowered.

The softening point of the tackifier (B) is preferably 60 ° C or higher, more preferably 70 ° C or higher, further preferably 80 ° C or higher, and particularly preferably 110 ° C or higher. Moreover, 160 degrees C or less is preferable, 150 degrees C or less is more preferable, and 130 degrees C or less is especially preferable. If it is less than 60 ° C., tackiness remains in the dried coating film, which may affect workability. When it exceeds 160 degreeC, adhesiveness with a polyolefin base material may be inferior. The softening point can be measured from ISO4625-1: 2004. The number average molecular weight is preferably 500 or more, more preferably 700 or more, further preferably 800 or more, preferably 1800 or less, more preferably 1600 or less, and further preferably 1500 or less. If it is less than 500, the physical properties of the coating film made of the adhesive composition may be lowered, or the surface of the coating film may bleed out. If it exceeds 1800, the compatibility with the acid-modified polyolefin (A) becomes poor. Sometimes.

<Organic solvent (C)>
The organic solvent (C) used in the present invention is not limited as long as it dissolves the acid-modified polyolefin (A) and the tackifier (B). However, the hydrocarbon solvent (C1) and the ester solvent and / or It is preferable to include a polar solvent (C2) composed of a ketone solvent. By containing the hydrocarbon solvent (C1) and the polar solvent (C2), the excellent storage stability of the adhesive composition can be expressed.

The hydrocarbon solvent (C1) is not limited as long as it dissolves the acid-modified polyolefin (A). Aromatic hydrocarbon solvents such as toluene and xylene, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane And chain hydrocarbon solvents such as n-hexane and n-heptane. Among these, alicyclic hydrocarbon solvents such as cyclohexane and methylcyclohexane are preferable from the viewpoint of solubility and environment.

The polar solvent (C2) is an organic solvent composed of an ester solvent and / or a ketone solvent, and plays a role in adjusting the viscosity of the adhesive composition and suppressing the increase in viscosity. When the organic solvent (C) is only the hydrocarbon solvent (C1), the viscosity of the adhesive composition generally becomes high, or the viscosity increases with time, which may hinder the coating workability. Examples of ester solvents include methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, tert-butyl acetate, amyl acetate, and isoamyl acetate. Of these, n-butyl acetate is preferred. Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Of these, methyl ethyl ketone is preferred. These may be used individually by 1 type and may be used in combination of 2 or more type.

The content (mass ratio) of the hydrocarbon solvent (C1) and the polar solvent (C2) is preferably (C1) / (C2) = 99 to 50/1 to 50, more preferably 97 to 60 / 3 to 40, more preferably 95 to 70/5 to 30. If (C2) is less than 1 part by mass, the viscosity of the adhesive composition may increase, or the viscosity may increase over time, which may hinder coating workability. If it exceeds 50 parts by mass, the solubility of the acid-modified polyolefin (A) may be reduced, the appearance of the adhesive composition may become turbid, or gelation or precipitation of the acid-modified polyolefin (A) may occur. Moreover, the wettability with a low polarity base material may fall, and the problem of coating workability | operativity and the fall of the adhesiveness of a low polarity base material and an adhesive bond layer may be caused.

The adhesive composition of the present invention may further contain an alcohol solvent (C3) as the organic solvent (C) in addition to the hydrocarbon solvent (C1) and the polar solvent (C2). Since the alcohol solvent (C3) is more polar than the ester solvent and the ketone solvent, the effect of adjusting the viscosity and suppressing the increase in viscosity is greater. Examples of the alcohol solvent (C3) include methanol, ethanol, propanol, isopropanol (IPA), n-butanol, isobutanol, 2-butanol and the like. The content of the alcohol solvent (C3) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and 5% by mass or less in 100% by mass of the organic solvent (C). Preferably, it is 3 mass% or less. If the amount is too small, the viscosity of the adhesive composition may increase, and workability may decrease. On the other hand, if the amount is too large, the storage stability may decrease.

When the organic solvent (C) contains a hydrocarbon solvent (C1), a polar solvent (C2) and an alcohol solvent (C3), the alcohol solvent (C3) is a hydrocarbon solvent (C1) and a polar solvent. The total amount of (C2) is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, and still more preferably 0.8 to 2 parts by mass. .

The organic solvent (C) is preferably 100 parts by mass or more, more preferably 150 parts by mass or more, with respect to 100 parts by mass in total of the acid-modified polyolefin (A) and the tackifier (B). Preferably it is 200 mass parts or more, Most preferably, it is 300 mass parts or more. If the amount is too small, the storage stability of the adhesive composition may be lowered. Moreover, it is preferable that it is 3000 mass parts or less, More preferably, it is 2000 mass parts or less, More preferably, it is 1500 mass parts, Most preferably, it is 1000 mass parts. Too much can be industrially disadvantageous.

The organic solvent (C) preferably contains 80% by mass or more, more preferably 90% by mass, of the hydrocarbon solvent (C1), polar solvent (C2) and alcohol solvent (C3), More preferably, it is 95 mass% or more, and it may be 100 mass%. If the amount is too small, the solution stability may decrease.

The adhesive composition of the present invention preferably contains no water from the viewpoint of the drying property of the adhesive layer after coating. Usually, the content of water in the adhesive composition may be 5% by mass or less, more preferably 1% by mass or less, and most preferably 0.1% by mass.

In addition, various additives such as fillers, pigments, colorants, antioxidants, and curing agents may be blended in the adhesive composition of the present invention as long as the adhesive performance is not deteriorated.

<Adhesive layer>
An adhesive layer can be produced using the adhesive composition of the present invention. The adhesive layer of the present invention refers to a layer of the adhesive composition after the adhesive composition is applied to a substrate, dried, and cured by aging or the like. As a lamination method, a general laminate manufacturing technique can be used. For example, although not particularly limited, the adhesive composition is applied to the surface of the substrate using an appropriate application means such as a roll coater or a bar coater, and dried. After drying, while the layer (adhesive layer) of the adhesive composition formed on the surface of the base material is in a molten state, another base material can be laminated and bonded (laminar bonding) to the coated surface. The thickness of the adhesive layer is not particularly limited, but is preferably 0.5 to 10 μm, more preferably 0.8 to 9.5 μm, and even more preferably 1 to 9 μm.

<Laminated body>
The laminate of the present invention is a two-layer laminate (base material 1 / adhesive layer) of the adhesive layer and the base material 1, or a three-layer laminate in which the base material 2 is bonded to the surface of the adhesive layer. Body (base material 1 / adhesive layer / base material 2), and further laminated body (base material 1 / adhesive layer / base material 2 / adhesive layer / Refers to the substrate 3).

The substrate is not particularly limited, but a polyolefin resin substrate is preferable. As the polyolefin resin substrate, for example, polyethylene, polypropylene, ethylene-propylene copolymer and the like can be used, and among them, polyethylene is preferable. The polyolefin-based resin base material may be blended with pigments and various additives as necessary, or may be subjected to surface treatment.

Since the adhesive composition obtained in the present invention is excellent in adhesion to polyolefin resin substrates, it can be used for primers, paints, inks, coating agents, and adhesives for painting, printing, adhesion, and coating. Useful.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.

<Measurement of acid value>
The acid value (mgKOH / g-resin) in the present invention is the amount of KOH required to neutralize 1 g of the acid-modified polyolefin (A). According to the test method of JIS K0070 (1992), It was measured. Specifically, 1 g of acid-modified polyolefin was dissolved in 100 g of xylene adjusted to a temperature of 100 ° C., and then a 0.1 mol / L potassium hydroxide ethanol solution [trade name “0” was used at the same temperature with phenolphthalein as an indicator. .1 mol / L ethanolic potassium hydroxide solution ", manufactured by Wako Pure Chemical Industries, Ltd.]. At this time, the amount of potassium hydroxide required for the titration was converted to mg, and the acid value (mgKOH / g) was calculated.

<Measurement of average molecular weight>
In the present invention, the weight average molecular weight (Mw) of the acid-modified polyolefin (A) is a gel permeation chromatograph Alliance e2695 (hereinafter GPC, standard material: polystyrene resin, mobile phase: tetrahydrofuran, column: SHODEX KF-806, manufactured by Japan Waters Co., Ltd.). + KF-803, column temperature: 40 ° C., flow rate: 1.0 ml / min, detector: photodiode array detector (wavelength 254 nm = ultraviolet)).
The number average molecular weight (Mn) of the tackifier (B) is a gel permeation chromatograph Alliance e2695 (hereinafter, GPC, standard material: polystyrene resin, mobile phase: tetrahydrofuran, column: TSKgel SuperHM-L, manufactured by Nippon Waters Co., Ltd.). Measurement was carried out using a triple connection, column temperature: 40 ° C., flow rate: 1.0 ml / min, detector: photodiode array detector (wavelength 254 nm = ultraviolet).

<Measurement of melting point>
The melting point in the present invention is determined by using a differential scanning calorimeter (hereinafter DSC, manufactured by TA Instruments Japan, Q-2000) at a rate of 10 ° C./min. This is a value measured from the top temperature of the melting peak when melting at elevated temperature.

<Evaluation of adhesiveness>
Evaluation of adhesiveness was performed by a shear test.
Using the # 16E wire bar on a 2 mm thick, 25 mm × 100 mm high density polyethylene test piece manufactured by Partec Co., Ltd. The test piece was coated so that the end of the test piece had a length of about 1 cm, and the film thickness after drying was 5 μm, and was dried with a hot air dryer at 80 ° C. for 10 minutes. The untreated surface of a 25 μm × 200 mm size 60 μm thick OPP film is bonded to the coated surface immediately after taking out from the dryer so that the chuck grip is in the same direction, and a load of 120 kg / m 2 is applied in an oven at 80 ° C. Aging was performed for 10 minutes to obtain an adhesion test sample. The adhesion test sample was allowed to stand at room temperature overnight and then subjected to a peel test using a tensile tester (“RTM-100” manufactured by Orientec). As for the pulling condition, the end of the polyethylene test piece was held on one side of the chuck of the testing machine, and the end of the OPP film was held on the other side. A 5 kgf load cell was used, and the 180 ° peel test was performed by pulling up and down at a pulling speed of 50 mm / min. . The test was carried out four times, and the average value of the measured strengths was taken as the peel strength.
(Judgment)
Peel strength ◎: 3.0 N / cm or more ○: 2.5 N / cm or more, less than 3.0 N / cm Δ: 2.0 N / cm or more, less than 2.5 N / cm ×: Less than 2.0 N / cm

<Evaluation of water resistance>
The adhesive compositions obtained in the Examples and Comparative Examples were applied to a 25 μm thick OPP film using a # 40E wire bar so that the film thickness after drying was 10 μm, and then heated at 80 ° C. and 30 ° C. with a hot air dryer. Let dry for minutes. The obtained coating film was cut into 2.5 cm × 30 cm strips, stored in a desiccator containing silica gel for 24 hours, and dried to obtain a strip-shaped coating film (water resistance test sample). Subsequently, each strip-shaped coating film was taken out, put into a hermetic metal can, and the coating film weight (X) was precisely weighed. Remove the strip-shaped coating film from the metal can, immerse it in 40 ° C warm water for 5 minutes, remove it, carefully wipe off the water adhering to the surface with gauze, and put it again into a sealed metal can weight (Y) Was precisely weighed. The weight increase rate of the coating film due to water absorption before and after immersion in warm water was calculated by the following formula and used as an index of water resistance. The evaluation criteria were as follows according to the weight increase rate of the coating film.
Formula: Weight increase rate after immersion in warm water (%) = (Coating film weight (Y) −Coating film weight (X)) / Coating film weight (X) × 100
(Judgment)
◎: Weight increase rate after warm water immersion less than 2.5% ○: Weight increase rate after warm water immersion 2.5% or more, less than 3.0% △: Weight increase rate after warm water immersion 3.0% or more, 3 Less than 5% ×: Weight increase rate after immersion in hot water 3.5% or more

<Measurement of viscosity>
The viscosity of the adhesive composition was measured at 25 ° C. using a Brookfield viscometer TVB-10M (hereinafter also referred to as B-type viscometer) manufactured by Toki Sangyo Co., Ltd.

<Storage stability evaluation>
The adhesive compositions prepared in Examples and Comparative Examples were stored in a stationary state in an incubator at 25 ° C. The changes in the appearance of the solution after being allowed to stand for 2 weeks were observed, and the results were evaluated according to the following criteria.
(Judgment)
(Double-circle): The adhesive composition has the fluidity equivalent to the time of preparation, without an external appearance change.
○: The adhesive composition is cloudy in appearance, but retains fluidity equivalent to that at the time of preparation.
(Triangle | delta): The adhesive composition has isolation | separation and sediment slightly, or is thickened.
X: Separation / sediment is generated in the adhesive composition or it is solidified and has no fluidity.

<Production example of acid-modified polyolefin (A)>
Production Example 1
In a 1 L autoclave, propylene / 1-butene copolymer (melting point 70 ° C., propylene / 1-butene = 75/25 (molar ratio)) 100 parts by mass, toluene 233 parts by mass and maleic anhydride 15 parts by mass, di-tert 4 parts by weight of butyl peroxide were added. The mixture was heated with stirring and reacted at 140 ° C. for 1 hour. The obtained reaction solution was cooled to 100 ° C., poured into a container containing 950 parts by mass of methyl ethyl ketone while stirring, and cooled to 25 ° C. to precipitate a resin. The slurry liquid containing the resin was centrifuged to separate the acid-modified propylene / 1-butene copolymer grafted with maleic anhydride from (poly) maleic anhydride and low molecular weight substances.
Further, the acid-modified propylene / 1-butene copolymer taken out by centrifugation was charged into a container containing 2000 parts by mass of methyl ethyl ketone, which had been kept at 25 ° C. while stirring, and stirring was continued for 1 hour. . Thereafter, the slurry was centrifuged to further separate the acid-modified propylene / 1-butene copolymer, (poly) maleic anhydride and low molecular weight product. This operation was repeated twice for purification.
After purification, it is dried at 60 ° C. under reduced pressure for 5 hours to give an acid-modified polyolefin, maleic anhydride-modified propylene / 1-butene copolymer (A-1, acid value 18 mgKOH / g, weight average molecular weight 70,000, Melting point 70 ° C., propylene / 1-butene = 75/25 (molar ratio)).

Production Example 2
The same procedure as in Production Example 1 was carried out except that the amount of maleic anhydride charged was changed to 20 parts by mass and that of di-tert-butyl peroxide was changed to 5 parts by mass. A 1-butene copolymer (A-2, acid value 25 mgKOH / g, weight average molecular weight 60,000, melting point 70 ° C., propylene / 1-butene = 75/25 (molar ratio)) was obtained.

Production Example 3
The propylene / 1-butene copolymer was changed to one having a melting point of 80 ° C. and propylene / 1-butene = 80/20 (molar ratio), the amount of maleic anhydride charged was 10 parts by mass, and di-tert-butyl peroxide. The maleic anhydride-modified propylene / 1-butene copolymer (A-3, acid value 11 mgKOH / g, weight), which is an acid-modified polyolefin, was operated in the same manner as in Preparation Example 1 except that the amount of feed was changed to 3 parts by mass. Average molecular weight 90,000, melting point 80 ° C., propylene / 1-butene = 80/20 (molar ratio)).

Production Example 4
Maleic anhydride, which is an acid-modified polyolefin, was operated in the same manner as in Production Example 1 except that the propylene / 1-butene copolymer was changed to one having a melting point of 95 ° C. and propylene / 1-butene = 85/15 (molar ratio). A modified propylene / 1-butene copolymer (A-4, acid value 18 mgKOH / g, weight average molecular weight 70,000, melting point 93 ° C., propylene / 1-butene = 85/15 (molar ratio)) was obtained.

<Unmodified polyolefin>
As the unmodified polyolefin (A-5), the propylene / 1-butene copolymer used in Production Example 1 (acid value 0 mg KOH / g, melting point 70 ° C., propylene / 1-butene = 75/25 (molar ratio)) Was used without modification.

Example 1
In a 500 ml four-necked flask equipped with a water-cooled reflux condenser and a stirrer, 100 parts by mass of the maleic anhydride-modified propylene / 1-butene copolymer (A-1) obtained in Production Example 1 as a resin and 30 parts by mass of tackifier B-1 was charged. Further, 463 parts by mass of methylcyclohexane, 52 parts by mass of n-butyl acetate and 5 parts by mass of 2-butanol were charged as solvents. The temperature was raised to 80 ° C. while stirring, and stirring was continued for 1 hour, followed by cooling to obtain an adhesive composition. Each evaluation was implemented about this adhesive composition. The results are shown in Tables 1 and 2.

Examples 2 to 10, Comparative Examples 1 to 5
An adhesive composition was prepared in the same manner as in Example 1, except that the amounts of acid-modified polyolefin (A), tackifier (B) and organic solvent (C) were changed as shown in Tables 1 and 2. Each evaluation was carried out.

Comparative Example 6
In a 500 ml four-necked flask equipped with a water-cooled reflux condenser and a stirrer, 100 parts by mass of maleic anhydride-modified propylene / 1-butene copolymer (A-1) and 30 parts by mass of tackifier B-1 , And 300 parts by mass of tetrahydrofuran were charged. After heating and dissolving at 60 ° C., 4 parts by mass of triethylamine was added, and then 25 parts by mass of “Neopelex (registered trademark) G-65” (alkylbenzene sulfonic acid system; solid content 65%) manufactured by Kao Corporation was added as an emulsifier. It melt | dissolved and added to the mass part tetrahydrofuran, and stirred uniformly. Next, 600 parts by mass of deionized water was added dropwise, stirred at 60 ° C. for 30 minutes, and then cooled to 40 ° C. After distilling off the organic solvent / water under reduced pressure, the concentration was adjusted by adding water to obtain an emulsion adhesive composition (resin content 30%). Each evaluation was implemented about this adhesive composition.

[Supplement under rule 26 15.01.2019]

The tackifiers shown in Tables 1 and 2 are as follows.
B-1: Yasuhara Chemical's styrene-modified terpene resin (YS resin TO125, softening point: 125 ° C)
B-2: Styrene-modified terpene resin (YS resin TO115, softening point: 115 ° C.) manufactured by Yasuhara Chemical
B-3: Yasuhara Chemical terpene phenol resin (YS Polystar T130, softening point: 130 ° C.)
B-4: Terpene resin from Yasuhara Chemical (YS Resin PX1250, softening point: 125 ° C.)
B-5: Yasuhara Chemical styrene resin (YS Resin SX100, softening point: 100 ° C.)

The adhesive composition according to the present invention has good adhesion performance, water resistance and chemical resistance to olefin-based tree substrates such as polyethylene and polypropylene, and can be applied at low temperature drying. It can be used as an adhesive for base materials such as polyethylene pipes, bottles and labels.

Claims

An adhesive composition containing an acid-modified polyolefin (A), a tackifier (B), and an organic solvent (C), wherein the tackifier (B) is a styrene-modified terpene resin. object. *
The adhesive composition according to claim 1, wherein the acid value of the acid-modified polyolefin (A) is 2 to 50 mgKOH / g.
The adhesive composition according to any one of claims 1 to 2, wherein the melting point of the acid-modified polyolefin (A) is 50 to 95 ° C.
The acid-modified polyolefin (A) contains propylene and 1-butene as olefin components, and the molar ratio of propylene to 1-butene is propylene / 1-butene = 98 to 60/2 to 40. 4. The adhesive composition according to any one of 3.
The adhesive composition according to any one of claims 1 to 4, wherein the tackifier (B) is in the range of 5 to 80 parts by mass with respect to 100 parts by mass of the acid-modified polypropylene (A). .
The adhesive according to any one of claims 1 to 5, wherein the organic solvent (C) contains a hydrocarbon solvent (C1) and a polar solvent (C2) comprising an ester solvent and / or a ketone solvent. Composition.
The adhesive composition according to claim 6, wherein the organic solvent (C) further contains an alcohol solvent (C3).
The adhesive composition according to any one of claims 1 to 7, which is used for adhesion of a polyethylene substrate.
A polyethylene-based laminate bonded with the adhesive composition according to any one of claims 1 to 8.