JPWO2019003737A1 - Emulsion and adhesive composition containing copolymerized polyolefin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an emulsion having good storage stability and excellent adhesion to a substrate. An emulsion containing a copolymerized polyolefin and a tackifier and satisfying the following (1) to (3). (1) The copolymerized polyolefin is an ethylene- (meth) acrylic acid ester-maleic anhydride terpolymer (2) The copolymerized polyolefin is dispersed in water (3) Dispersion particles composed of the copolymerized polyolefin Contains tackifier [Selection diagram] None

Description

  The present invention relates to an emulsion that exhibits good adhesion performance to an olefin resin base material such as polyethylene or polypropylene.

  Research has been conducted for a long time on a method of adhering a substrate having a low surface energy such as polyethylene or polypropylene, and it is known that it is not easy to design an adhesive having high adhering performance to these materials. As a method to develop good adhesion to these low surface energy substrates, we propose a technique of pretreating the surface of the adherend by corona discharge or plasma treatment in advance to increase the surface energy before adhesion. Has been done. While these techniques are effective techniques, they also require expensive equipment and increase power consumption.

  On the other hand, products using olefin-based materials such as polyethylene and polypropylene have been increasing in many senses from household products around us to various industrial uses. Particularly for automotive applications, the mounting of molding materials made of polypropylene is being actively promoted due to the trend of weight reduction of automobiles. Due to such circumstances, more effective adhesives that have never existed before have been developed in recent years. In addition, due to work environment problems, adhesives are changing from conventional organic solvent-based adhesives to more environmentally friendly water-based adhesives.

  Tackifiers are used for the above-mentioned adhesives for the purpose of imparting tackiness, improving adhesiveness, etc. For example, Patent Document 1 describes an aqueous dispersion containing a polyolefin resin and a tackifier. Has been done.

Japanese Patent No. 4033732

  When the tackifier is used as the adhesive as described above, it is important to select the tackifier according to the substrate (adherend). However, in Patent Document 1 described above, since a method of mixing a tackifier dispersed in water with an emulsifier and a polyolefin resin aqueous dispersion is adopted, a tackifier that is difficult to disperse in water cannot be used, Even when a water-dispersible tackifier is used, there is a possibility that the storage stability of the aqueous dispersion may be adversely affected by the interaction with the polyolefin resin aqueous dispersion. In particular, olefin base materials such as polyethylene and polypropylene have a low polarity and an SP value of around 8.0, which is extremely low. Therefore, in order to improve the adhesiveness to these base materials, adhesion with a relatively close SP value is used. Although it is necessary to use a tackifier, such a tackifier is poor in hydrophilicity, so that it has been difficult to mix it with the polyolefin resin aqueous dispersion. Therefore, a polyolefin resin aqueous dispersion which can utilize various tackifiers depending on the adherend has been desired.

  The present invention is an emulsion containing a polyolefin resin and a tackifier, which has excellent storage stability regardless of the type of the tackifier and exhibits good adhesion performance to an olefin resin substrate such as polyethylene or polypropylene. Another object of the present invention is to provide an adhesive composition containing the emulsion.

  In order to achieve the above object, the present inventors have conducted extensive studies and have proposed the following invention.

That is, the present invention is an emulsion containing a copolymerized polyolefin and a tackifier and satisfying the following (1) to (3).
(1) The copolymerized polyolefin is an ethylene- (meth) acrylate-maleic anhydride terpolymer (2) The copolymerized polyolefin is dispersed in water (3) Dispersion particles made of the copolymerized polyolefin Contains tackifier

  The 50% number-average particle diameter of the tackifier-encapsulated copolymerized polyolefin dispersion particles is preferably more than 100 nm.

  The tackifier is preferably in the range of 5 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the copolymerized polyolefin resin.

  The emulsion described in any of the above can be used as an adhesive composition and an adhesive for polyolefin resin.

  The emulsion of the present invention has good storage stability because the copolymerized polyolefin is uniformly and stably dispersed in water in the form of fine particles with the tackifier included. Furthermore, since an emulsion and an adhesive composition can be prepared regardless of the type of tackifier, the adhesiveness to a substrate is excellent.

Embodiment of the invention

  Embodiments of the present invention will be described below.

<Copolymerized polyolefin>
The copolymerized polyolefin used in the present invention is a terpolymer containing ethylene, (meth) acrylic acid ester, and maleic anhydride as constituent units. The copolymerized polyolefin may be any of a random copolymer of ethylene, (meth) acrylic acid ester, maleic anhydride, a block copolymer and a graft copolymer, but a random copolymer is preferable.

  When the total of the ethylene component, the (meth) acrylic acid ester component and the maleic anhydride component is 100% by mass, the content of the ethylene component is preferably 50% by mass or more and 95% by mass or less, more preferably 50% by mass or more. It is at least mass% and less than 95 mass%, more preferably at least 60 mass% and at most 90 mass%, particularly preferably at least 70 mass% and at most 80 mass%. When the content of the ethylene component is less than 50% by mass, the hydrophobicity of the copolymerized polyolefin is too low, and thus the adhesiveness to the olefin substrate may be reduced. When the content of the ethylene component is more than 95% by mass, the crystallinity of the copolymerized polyolefin becomes high, which may make water dispersion difficult.

  Examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate. Can be mentioned. In addition, "(meth) acrylic acid" refers to "acrylic acid or methacrylic acid." When the total of the ethylene component, the (meth) acrylic acid ester component and the maleic anhydride component is 100% by mass, the content of the (meth) acrylic acid ester component is preferably 5% by mass or more and 49% by mass or less. , More preferably 10% by mass or more and 40% by mass or less, and further preferably 15% by mass or more and 30% by mass or less. The most preferable range is 18% by mass or more and 29% by mass or less. When the content of the (meth) acrylic acid ester component is less than 5% by mass, the copolymerized polyolefin has a high melting point and may not be suitable for use as an olefin base material. When the content of the (meth) acrylic acid ester component is larger than 49% by mass, the crystallinity of the copolymerized polyolefin may be remarkably reduced and the adhesiveness may be lowered.

  When the total of the ethylene component, the (meth) acrylic acid ester component and the maleic anhydride component is 100% by mass, the content of the maleic anhydride component is preferably 0.01% by mass or more and 5% by mass or less, It is more preferably 0.1% by mass or more and 4% by mass or less, and further preferably 1% by mass or more and 3% by mass or less. The most preferable range is 1.5% by mass or more and 2.5% by mass or less. When the content of the maleic anhydride component is less than 0.01% by mass, it may be difficult to disperse the copolymerized polyolefin in water. When the content of the maleic anhydride component is more than 5% by mass, the polarity of the copolymerized polyolefin becomes large and the adhesiveness to a low polar substrate such as olefin may be deteriorated.

  The melting point of the copolymerized polyolefin is preferably 50 ° C or higher and 150 ° C or lower, more preferably 55 ° C or higher and 100 ° C or lower, and further preferably 60 ° C or higher and 90 ° C or lower. When the melting point of the copolymerized polyolefin is lower than 50 ° C, the heat resistance when used as an adhesive may be poor. When the melting point of the copolymerized polyolefin is higher than 150 ° C, it may not be suitable for use as an olefin base material.

  The MFR (melt flow rate) of the copolymerized polyolefin at 190 ° C. under a load of 2160 g is preferably 0.1 g to 300 g / 10 minutes, more preferably 1 g to 100 g / 10 minutes, and further preferably 3 g to 30 g / 10 minutes. Is. If the MFR is less than 0.1 g / 10 minutes, resin sagging may occur when used as an adhesive. If the MFR is more than 300 g / 10 minutes, the wettability to the substrate may be poor and the adhesiveness may be lowered.

  The acid value of the copolymerized polyolefin is preferably 0.1 mgKOH / g or more and 56 mgKOH / g or less, more preferably 1 mgKOH / g or more and 45 mgKOH or less, and further preferably 11 mgKOH / g or more and 34 mgKOH / g or less. The most preferable range is 16 mgKOH / g or more and 28 mgKOH / g or less. When the acid value is less than 0.1 mgKOH / g, it may be difficult to disperse the copolymerized polyolefin in water. When the acid value is larger than 56 mgKOH / g, the polarity of the copolymerized polyolefin becomes large and the adhesiveness to a low polar substrate such as olefin may be deteriorated.

<Tackifier>
The tackifier used in the present invention is not particularly limited, and a rosin-based resin, a terpene-based resin, a coumarone resin, a petroleum resin or the like may be used depending on the substrate. The content of the tackifier is preferably 5 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the copolymerized polyolefin. It is more preferably 10 parts by mass or more and 50 parts by mass or less, and further preferably 20 parts by mass or more and 40 parts by mass or less. If the content of the tackifier is less than 5 parts by mass, the effect of blending the tackifier may not be obtained. When the content of the tackifier is more than 80 parts by mass, the tackifier cannot be completely contained in the dispersion particles of the copolymerized polyolefin, which may result in an unstable emulsion.

  Although the softening point of the tackifier is not particularly limited, it is preferably 60 ° C. or higher and 160 ° C. or lower, more preferably 70 ° C. or higher and 150 ° C. or lower, and further preferably 80 ° C. or higher and 145 ° C. or lower from the viewpoint of adhesiveness and heat resistance. It is most preferably 86 ° C or higher and 140 ° C or lower. When the softening point of the tackifier is less than 60 ° C, the heat resistance when used as an adhesive may be insufficient. When the softening point of the tackifier exceeds 160 ° C., the wettability to the substrate is poor and the adhesiveness may be reduced.

The SP value of the tackifier is also not particularly limited, and an appropriate tackifier may be selected according to the base material. For example, for polyolefins such as polyethylene and polypropylene, the SP value of the tackifier is preferably 8.4 to 8.9 (J / cm ³ ) ^1/2 as calculated by Hoy. It is more preferably 8.5 to 8.8 (J / cm ³ ) ^1/2 . It is known that the SP value (δ) of a polymer compound such as a tackifier according to the Hoy's formula is determined as follows.
δ (polymer compound) = ρΣE / M
Here, ρ is the density of the polymer compound, M is the molecular weight of the repeating structural unit of the polymer compound, and E is the molar cohesive energy constant of each structural unit constituting the polymer compound. The value of E can use the value published in various documents. Examples of documents in which numerical values are described include J. Paint Technology vol. 42 76-118 (1970).

<Emulsion>
The emulsion of the present invention contains a copolymerized polyolefin and a tackifier, (1) the copolymerized polyolefin is an ethylene- (meth) acrylic acid ester-maleic anhydride terpolymer, and (2) the copolymerized polyolefin. Is dispersed in water, and (3) the dispersion particles of the copolymerized polyolefin include the tackifier (hereinafter, also referred to as the tackifier-encapsulated copolymerized polyolefin dispersion particles).

  The emulsion has good storage stability because the dispersion particles of the copolymerized polyolefin encapsulate the tackifier and are uniformly and stably dispersed in water in the form of fine particles. Furthermore, since an emulsion and an adhesive composition can be prepared regardless of the type of tackifier, the adhesiveness to a substrate is excellent.

  In the emulsion of the present invention, as the inclusion state of the copolymerized polyolefin and the tackifier, the ethylene chain portion (hydrophobic portion) of the copolymerized polyolefin is inside, and the carboxyl group portion derived from maleic anhydride (hydrophilic portion) is outside. As the dispersion particles (micelle particles), the tackifier is included inside the copolymerized polyolefin. Furthermore, it is considered that the hydrophilic part of the copolymerized polyolefin is neutralized with a basic substance. This means that the tackifier, which cannot be stably dispersed or dissolved in water by itself, phase-separates and precipitates in water, does not phase-separate and precipitate in the emulsion of the present invention, and exists in a uniform and stable state. It can be estimated from that. It can also be inferred from the fact that as the blending amount of the tackifier increases, the particle size of the dispersion particles increases proportionally up to a certain amount.

  The 50% number average particle diameter of the copolyolefin dispersion particles containing the tackifier in the emulsion is preferably larger than 100 nm. If the particle size is 100 nm or less, the adhesiveness may be reduced. Although the factor that reduces the adhesiveness is not clear, when the particle size is 100 nm or less, the compatibility of the tackifier and the copolymerized polyolefin is remarkably high, and when used as an adhesive, the tackifier wets the base material interface. It is speculated that it does not spread. The particle size is more preferably 110 nm or more, and further preferably 120 nm or more. Further, the upper limit of the particle diameter is preferably 500 nm or less. It is more preferably 400 nm or less, still more preferably 300 nm or less, and particularly preferably 200 nm or less. If the particle size is larger than 500 nm, the storage stability of the emulsion may decrease.

  It is preferable to use an emulsifier when preparing the emulsion of the present invention from the viewpoint of dispersion stability and storage stability. The emulsifier is not particularly limited, and examples thereof include an anionic emulsifier, a cationic emulsifier, a nonionic emulsifier (nonionic emulsifier), an amphoteric emulsifier, and a reactive emulsifier. Among these, nonionic emulsifiers are particularly preferable. The HLB of the nonionic emulsifier is preferably 10 or more. HLB is an index (an acronym for Hydrophile-Lipophile Balance) that represents the balance between hydrophilicity and lipophilicity of an emulsifier, and the higher the value of HLB, the greater the hydrophilicity. This is a method devised by Griffin. When the HLB of the nonionic emulsifier used is less than 10, the lipophilicity of the emulsifier is too strong, so that the effect of dispersion stability of the emulsion is small and the dispersion stability may be worse than that of the emulsion containing no emulsifier. . The more preferable HLB of the nonionic emulsifier is 12 or more, and the more preferable HLB is 16 or more. The upper limit of HLB is not particularly limited, but 19 or less is preferable.

  The type of the nonionic emulsifier is not particularly limited as long as HLB is 10 or more. For example, polyoxyalkylene alkyl ether type such as polyoxyethylene lauryl ether and polyoxyethylene such as polyoxyethylene styrenated phenyl ether. Alkylene styrenated phenyl ether type, polyoxyalkylene alkylphenyl ether type such as polyoxyethylene nonylphenyl ether, polyoxyalkylene alkylamine type such as polyoxyethylene stearyl amine, polyoxyalkylene amine such as polyoxyethylene polyoxypropylene monoamine Type, polyoxyalkylene alkylamide type such as polyoxyethylene oleylamide, polyoxyalkylene fatty acid ester type such as polyoxyethylene monolaurate, Ethylene oxide propylene oxide block polymerization type such as cyethylene polyoxypropylene glycol, polyoxyethylene polyoxypropylene tridecyl ether, etc. Polyethylene oxide propylene oxide random polymerization type, polyoxyethylene sorbitan fatty acid ester such as polyoxyethylene sorbitan monostearate, etc. Is mentioned.

  The emulsifiers may be used alone or in combination of two or more kinds, and different combinations of anionic emulsifier and nonionic emulsifier or two kinds of the same nonionic emulsifier may be combined. When a nonionic emulsifier is used in combination, it is preferable to use emulsifiers having different HLB.

  The addition amount of the emulsifier is preferably 1 part by mass or more and 25 parts by mass or less, more preferably 3 parts by mass or more and 15 parts by mass or less, and further preferably 5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the copolymerized polyolefin. Is. When the addition amount of the emulsifier is less than 1 part by mass, the dispersion stability and the storage stability of the emulsion may be deteriorated and the copolymerized polyolefin may be precipitated. If the added amount of the emulsifier is larger than 25 parts by mass, the adhesiveness to the substrate may be deteriorated due to bleed-out of the emulsifier.

  An example of the method for preparing the emulsion of the present invention is shown below, but the invention is not limited to the following contents. That is, first, a copolymerized polyolefin and a tackifier are heated and dissolved in an ether solvent, an alcohol solvent, an aromatic solvent and water at a predetermined ratio, and an emulsifier is added to this, followed by addition of a basic substance. It can be obtained by removing the ether solvent, the alcohol solvent and the aromatic solvent after soaking and cooling.

  This will be described step by step.

  First, the copolymerized polyolefin and the tackifier are heated and dissolved in a predetermined ratio in an ether solvent, an alcohol solvent, an aromatic solvent and water.

  The ether solvent is not particularly limited, but includes tetrahydrofuran, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, etc. These may be used alone or in combination of two or more. it can. Of these, tetrahydrofuran is preferable.

  The alcohol solvent is not particularly limited, and examples thereof include an aliphatic alcohol having 1 to 7 carbon atoms, an aromatic alcohol, an alicyclic alcohol, and the like, and these may be used alone or in combination of two or more. it can. Examples of the aliphatic alcohol having 1 to 7 carbon atoms include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, pentanol and hexanol. Examples of aromatic alcohols include benzyl alcohol. Cyclohexane methanol etc. are mentioned as alicyclic alcohol. Among them, aliphatic alcohols having 1 to 7 carbon atoms are preferable, aliphatic alcohols having 3 to 5 carbon atoms are more preferable, and isopropyl alcohol is still more preferable.

  The aromatic solvent is not particularly limited, and examples thereof include benzene, toluene, xylene, ethylbenzene, isopropylbenzene, and solvent naphtha, and these can be used alone or in combination of two or more. Of these, toluene is preferable.

  The ratio of the ether solvent, the alcohol solvent and the aromatic solvent used is not particularly limited, but in a mass ratio, ether solvent: alcohol solvent: aromatic solvent = 100: 3-50: 3-50. It is preferable that it is, more preferably 100: 5 to 35: 5 to 35. If the proportion of the alcohol solvent with respect to 100 parts by mass of the ether solvent exceeds 50 parts by mass, the solubility of the copolymerized polyolefin at a high temperature during the manufacturing process may decrease, and uniform dispersion may not be possible. Further, when the proportion of the aromatic solvent exceeds 50 parts by mass, the particles are aggregated with each other and a large amount of aggregates are generated, and uniform dispersion may not be possible. If the proportion of the alcohol solvent or the aromatic solvent is less than 3 parts by mass, the effect may not be exhibited, and uniform dispersion may not be possible.

  In the mixed system before heating and dissolving the copolymerized polyolefin and the tackifier, the total amount of the copolymerized polyolefin and the tackifier, water, and the ratio of the total organic solvent of the ether solvent, the alcohol solvent and the aromatic solvent. Can be arbitrarily selected, but in the mass ratio, the total amount of the copolymerized polyolefin resin and the tackifier: water: total organic solvent = 100: 50 to 800: 10 to 900 is preferable, and 100: 50. It is more preferably 100-400: 50-450. When the amount of water or total organic solvent is large, the copolymerized polyolefin is more easily dispersed in water, but it takes time to concentrate and the volumetric efficiency is lowered, which is economically disadvantageous and not practical. When the amount of water is small, it is often impossible to disperse. When the total amount of organic solvent is small, the viscosity is remarkably increased at the time of dissolution by heating, uniform dissolution cannot be achieved, and eventually uniform dispersion may not be achieved.

  The temperature for melting by heating is not particularly limited, but is preferably 50 ° C or higher and 150 ° C or lower. When the melting temperature is 50 ° C. or lower, the copolymerized polyolefin resin may not be sufficiently dissolved. When the temperature is 150 ° C. or higher, the pressure resistance limit of the container may be exceeded. Although the dissolution time is not particularly limited, it is usually completed in 1 to 2 hours.

  The emulsifier may be added either before or after the copolymerized polyolefin and the tackifier are dissolved. As described above, the emulsifier is not particularly limited, and anionic emulsifier, cationic emulsifier, nonionic emulsifier (nonionic emulsifier), amphoteric emulsifier, reactive emulsifier and the like can be used.

  The basic substance may be added before or after the dissolution of the copolymerized polyolefin. Examples of the basic substance include, but are not limited to, morpholine; ammonia; amines such as methylamine, ethylamine, dimethylamine, triethylamine, ethanolamine, dimethylethanolamine, and the like. These may be used alone or in combination of two or more. It can be used in combination. A preferred basic substance is dimethylethanolamine. The amount of the basic substance used is preferably 1 to 5 chemical equivalents, more preferably 1.5 to 3.5 chemical equivalents, based on the carboxyl group of the copolymerized polyolefin. If it is less than 1 equivalent, the carboxyl groups of the copolymerized polyolefin may not be sufficiently neutralized. When the amount is more than 5 equivalents, the basicity is too strong and the acid-base balance of the dispersion may be lost, resulting in extremely high viscosity. As a method of adding the basic substance, the basic substance may be added as it is, or may be diluted with water for more uniform mixing and added. The time required for dispersion after adding the basic substance is not particularly limited, but is preferably 1 to 2 hours.

  Next, the organic solvent is removed from the obtained dispersion to obtain an emulsion. The organic solvent can be removed by distilling under reduced pressure. The degree of pressure reduction and temperature at the time of distilling off are not particularly limited, but are preferably about 90 to 95 KPa (absolute pressure) and about 20 to 60 ° C. At this time, part of the water is also distilled off. The composition (mass ratio) of the emulsion after distilling off the organic solvent and a part of water by vacuum distillation is as follows: copolymerized polyolefin: basic substance: water = 1: 0.06-0.33: 1.5-4 Is preferred. The residual amount of the organic solvent after distillation under reduced pressure is preferably 1 part by mass or less, more preferably 0.1 part by mass or less, and even 0 part by mass with respect to 100 parts by mass of the copolymerized polyolefin. Is particularly preferable. It should be noted that additional water can be added if necessary.

  The solid content concentration in the emulsion is preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more. Too little may not be practical. Further, it is preferably 50% by mass or less, more preferably 45% by mass or less, and further preferably 40% by mass or less. If it is too large, the storage stability may decrease. The solid content in the emulsion means the total amount of the copolymerized polyolefin, the tackifier, the emulsifier and the basic substance.

<Adhesive composition>
The adhesive composition of the present invention is a composition in which a curing agent is added to the emulsion as needed. The curing agent is not particularly limited, and examples thereof include a water-soluble polyfunctional epoxy resin, a water-soluble polyfunctional carbodiimide resin, an aqueous dispersion of a polyfunctional isocyanate compound, and a water-soluble silane coupling agent having a polyfunctional silyl group. . The curing agent is preferably 0.8 to 1.2 times equivalent functional amount (epoxy group amount, carbodiimide group amount, isocyanate group amount or silyl group amount) to the acid value of the copolymerized polyolefin, More preferably, it is 0.9 to 1.1 times equivalent. Of these, water-soluble polyfunctional epoxy resins are preferred. Specific examples of commercially available products include "Denacol (registered trademark) EX-512", "Denacol EX-521", "Denacol EX-614B", "Denacol EX-821", and "Denacol EX" manufactured by Nagase Chemtech Co., Ltd. -920 "and the like. These water-soluble epoxy resins can be added to the emulsion of the present invention at any ratio, but it is preferable that the water-soluble epoxy resin is blended so as to have an equivalent epoxy group equivalent to the acid value of the copolymerized polyolefin in the emulsion.

  In addition, various additives such as various fillers, pigments, colorants, and antioxidants may be added to the emulsion of the present invention within a range that does not impair the effects of the present invention. The content of the emulsion in the adhesive composition is preferably 60% by mass or more, more preferably 70% by mass or more, and further preferably 80% by mass or more. Further, it is preferably 99% by mass or less, and more preferably 95% by mass or less. Within the above range, the excellent effects of the present invention can be exhibited.

  Since the emulsion of the present invention has excellent adhesiveness to a polyolefin resin substrate, it is useful as a primer for coating, printing, adhering and coating, and as a paint, ink, coating agent and adhesive.

  The polyolefin resin base material may be appropriately selected from conventionally known polyolefin resins. For example, polyethylene, polypropylene, ethylene-propylene copolymer and the like can be used, although not particularly limited thereto. A pigment and various additives may be blended with the polyolefin resin base material as required.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In the examples and comparative examples, "part" simply means "part by mass". The measuring / evaluating methods adopted in the present invention are as follows.

1) Measurement of Acid Value of Copolymerized Polyolefin The acid value (mgKOH / g) in the present invention refers to the amount of KOH required to neutralize 1 g of the copolymerized polyolefin, and the test of JIS K0070 (1992). It measured according to the method. Specifically, 1 g of polyolefin was dissolved in 100 g of xylene whose temperature was adjusted to 100 ° C., and then phenolphthalein was used as an indicator at the same temperature to prepare a 0.1 mol / L potassium hydroxide ethanol solution [trade name: 0.1 mol / L ethanolic potassium hydroxide solution ", manufactured by Wako Pure Chemical Industries, Ltd.]. At this time, the acid value (mgKOH / g) was calculated by converting the amount of potassium hydroxide required for titration into mg.

2) Measurement of Emulsion Solid Content Concentration About 1 g of the sample emulsion is placed in a 50 ml glass weighing bottle and precisely weighed. Then, the weighing bottle from which the sample is taken is dried by a hot air dryer at 120 ° C. for 2 hours, the taken-out weighing bottle is put in a desiccator, and allowed to stand and cool at room temperature for 30 minutes. The weighing bottle is taken out from the desiccator, the mass is precisely weighed, and the mass% of the emulsion solid content concentration is calculated from the weight change before and after hot air drying (the following formula).
Emulsion solid content concentration (mass%) = [(sample mass before hot air drying)-(sample mass after hot air drying)] / (sample mass before hot air drying) × 100

3) Quantification of tackifier content The dry sample (resin) obtained by the above solid content measurement was dissolved in deuterated chloroform, and a nuclear magnetic resonance analyzer (NMR) "Gemini-400-MR" manufactured by Varian was used. The ratio between the copolymerized polyolefin and the tackifier was determined by ¹ H-NMR analysis.

4) Measurement of emulsion viscosity Using a "Viscometer TV-22" (E type viscometer) manufactured by Toki Sangyo Co., Ltd., a sample of rotor No. The measurement was performed under the conditions of 0.8 ° (= 48 ′) × R24, range H, rotation speed 5 rpm, and 25 ° C.

5) Measurement of emulsion pH The value at 25 ° C was measured using "pH meter F-52" manufactured by Horiba Ltd. The calibration of the measuring instrument is Wako Pure Chemical Industries, Ltd., pH standard solution of phthalate (pH: 4.01), pH standard solution of neutral phosphate (pH: 6.86), pH standard of borate. The measurement was carried out at 3 points using the solution (pH 9.18).

6) Emulsion (tackifier-containing copolymerized polyolefin dispersion particles) 50% number average particle size measurement A sample prepared at a concentration of 0.05 g / L using "Zetasizer Nano Nano-ZS Model ZEN3600" manufactured by Malvern Co. Was measured 3 times at 25 ° C. and taken as the average value.

7) Evaluation of Storage Stability of Emulsion The emulsions prepared in Examples and Comparative Examples were stored in an incubator at 5 ° C, 25 ° C, and 40 ° C in a stationary state, and changes with time in appearance of the emulsion were observed. The observation was performed after 1 week, 1 month, 3 months, 6 months, and 12 months, and the scores were given as follows. 5 points: No change in appearance after 12 months, 4 points: No change in appearance after 6 months (condensation / sedimentation of resin after that), 3 points: No change in appearance after 3 months (condensation / sedimentation of resin after that) ) 2 points: No change in appearance after 1 month (resin condensation and sedimentation after that), 1 point: No change in appearance after 1 week (resin condensation and sedimentation after that), 0 point: 1 week later There is resin aggregation / sedimentation.

8) Evaluation of LDPE base material adhesiveness Dynol (registered trademark) 604 (manufactured by Air Products Co., Ltd.) as a leveling agent was added to the emulsions obtained in Examples and Comparative Examples in an amount of 0.5% by mass based on the emulsion. The composition was applied to a low-density polyethylene (LDPE) film (Mipolon film, manufactured by Mitsuwa Co., Ltd.) having a thickness of 0.1 mm using a # 16E wire bar so that the thickness after drying would be 6 μm. It was dried for 3 minutes with a hot air dryer at ℃. Take out from the dryer, put the same LDPE film on the coating film, and hold it for 30 seconds at 80 ° C and a holding pressure of 0.3 MPa with a heat seal tester (TP-701-B heat seal tester manufactured by Tester Sangyo Co., Ltd.). Then, a sample for measuring LDPE adhesive strength was molded. After the adhesive strength measurement sample was left standing overnight at room temperature, it was cut into a width of 25 mm, and a Tensilon (RTG-1310, manufactured by A & D Co., Ltd.) was used to pull the sample up and down at a pulling speed of 50 mm / min. The 180 ° peel adhesive strength was measured by pulling. The same test was carried out 5 times, and the average value of the measured strengths was taken as the LDPE adhesive strength.

9) Evaluation of HDPE base material adhesiveness Dynol (registered trademark) 604 (manufactured by Air Products Co., Ltd.) as a leveling agent was added to the emulsions obtained in Examples and Comparative Examples in an amount of 0.5% by mass based on the emulsion. The composition was applied to a high-density polyethylene (HDPE) test piece (2.0 × 25 × 100 mm, manufactured by Nippon Test Panel Co., Ltd.) using a # 16E wire bar so that the thickness after drying was 6 μm. It was dried for 3 minutes in a hot air dryer at 80 ° C. After removing from the dryer, the same HDPE test piece was attached to the coated surface immediately afterwards so that the adhered part was 25 mm x 15 mm, and aged at 80 ° C for 5 minutes with a load of 120 kg / m ² and HDPE adhesion. A sample for strength measurement was obtained. After the adhesive strength measurement sample was left at room temperature overnight, the tensile shear adhesive strength was measured by pulling it up and down using Tensilon (RTG-1310, manufactured by A & D Co., Ltd.) at a pulling speed of 50 mm / min. did. The same test was performed 5 times, and the average value of the measured strengths was taken as the HDPE adhesive strength.

  The compositions of the copolymerized polyolefin and tackifier used in the following examples and comparative examples are shown in Tables 1 and 2.

Example 1
Deionized water 188 g, copolymerized polyolefin manufactured by Japan Polyethylene Corporation (“LEX Pearl (registered trademark) ET230X”; ethylene- (meth) acrylic acid ester-maleic anhydride terpolymer (mass ratio: 87.0-12) 0.0-1.0), MFR: 8.0 g / 10 minutes, melting point: 88 ° C., acid value: 11 mg KOH / g) 50 g, Yasuhara Chemical Co., Ltd. tackifier (“YS Polystar (registered trademark) T130”; terpene). 7.5 g of phenol resin, softening point: 130 ° C.), 70 g of tetrahydrofuran, 5 g of isopropyl alcohol and 5 g of toluene were put into an autoclave, heated to 120 ° C., and then heated and dissolved at the same temperature for 2 hours. Next, 5.0 g of an emulsifier manufactured by Dai-ichi Kogyo Co., Ltd. (“DKS (registered trademark) NL-180”; polyoxyethylene lauryl ether, HLB: 16.1) was added and further heated and dissolved for 1 hour. Thereafter, 2.5 g of dimethylethanolamine was added, dispersed for 1 hour, and then cooled to 40 ° C. (pre-emulsion). Then, the organic solvent / water was distilled off at a reduced pressure of 91 kPa (absolute pressure) to obtain a pure white cloudy uniform emulsion (1). The obtained emulsion (1) had a solid content concentration of 30.4 mass%, a viscosity at 25 ° C of 12.3 mPa · s, a pH of 8.7, and a 50% number average particle diameter of 140 nm. Further, it was confirmed by NMR that the content of the tackifier was 15 phr (15 parts by mass of the tackifier relative to 100 parts by mass of the copolymerized polyolefin) according to the charged composition ratio. Emulsion (1) was stored in an incubator at 5 ° C, 25 ° C, and 40 ° C, and the storage stability was evaluated. As a result, no change was observed in the appearance after 12 months. Moreover, when the LDPE base material adhesiveness and the HDPE base material adhesiveness were evaluated using the emulsion (1) according to the above procedure, they were respectively 3.9 N / cm and 2.5 MPa.

Examples 2-12
According to the combination of Table 3, emulsions (2) to (12) were obtained in the same manner as in Example 1 above. The physical properties and adhesiveness of the emulsion were measured by the methods described above. The composition and physical properties are shown in Table 3.

  Hereinafter, Comparative Example 1 is an example in which an attempt was made to prepare an emulsion using an ethylene- (meth) acrylic acid ester copolymer, and a uniform and stable emulsion was not obtained. Comparative Example 2 is an example in which an emulsion was prepared using an acid-modified polyolefin. Comparative Example 3 is an example in which emulsion particles of a copolymerized polyolefin resin do not include a tackifier. Comparative Example 4 is an example of an emulsion that contains a tackifier by adding a tackifier emulsion to the emulsion that does not include the tackifier and does not include the copolymerized polyolefin particles. Comparative Example 5 is an example in which only a tackifier was tried to be emulsified with an emulsifier and a uniform and stable emulsion was not obtained.

Comparative Example 1
Instead of the ethylene- (meth) acrylic acid ester-maleic anhydride terpolymer, a copolymerized polyolefin resin manufactured by Nippon Polyethylene Co., Ltd. (“Rex Pearl A4250”; ethylene- (meth) acrylic acid ester copolymer (mass) Ratio: 75.0-25.0), MFR: 5.0 g / 10 min, melting point: 92 ° C., acid value: 0 mg KOH / g) 50 g of the emulsion, except that 50 g was used. An attempt was made to prepare (13), but large amounts of coarse particles were generated during cooling, and a uniform dispersion could not be obtained.

  As a comparative example, an acid-modified polyolefin (A) was produced by the following method in order to use it instead of the copolymerized polyolefin. In a 3 L SUS autoclave reactor, 750 g of a propylene-ethylene copolymer produced using a metallocene catalyst (propylene: ethylene = 93: 7 molar ratio, melting point 75 ° C., melt viscosity at 180 ° C .: 1500 mPa · s). Then, 90 g of maleic anhydride, 15 g of dicumyl peroxide, and 1100 g of toluene were put and the mixture was sealed. After replacing the inside of the autoclave with nitrogen, the mixture was heated and reacted at an internal temperature of 140 ° C. for 5 hours. The reaction solution was cooled to 110 ° C., the reaction solution was placed in a 10 L SUS container containing 3500 g of methyl ethyl ketone (MEK), and the resin was precipitated, followed by solid-liquid separation to obtain a resin. The resin was further put into 1000 g of MEK, and washing for solid-liquid separation was repeated three times, and then the resin was dried to obtain an acid-modified polyolefin (A). The obtained acid-modified polyolefin (A) had a maleic anhydride content of 2.3% by mass and a weight average molecular weight of 34,000.

Comparative example 2
An emulsion (14) was prepared in the same manner as in Example 1 except that 50 g of the acid-modified polyolefin (A) was used instead of the ethylene- (meth) acrylic acid ester-maleic anhydride terpolymer. It was made. The physical properties and adhesiveness of the emulsion were measured by the methods described above. The composition and physical properties are shown in Table 4.

Comparative Example 3
An emulsion (15) was prepared in the same manner as in Example 1 above, except that the copolymerized polyolefin was used alone without using YS Polystar T130. The physical properties and adhesiveness of the emulsion were measured by the methods described above. The composition and physical properties are shown in Table 4.

Comparative Example 4
166 g (solid content: 50.2 g) of the emulsion (15) (solid content: 30.2 wt%), a tackifier manufactured by Harima Kasei Co., Ltd. (“Hariester SK-385NS”; rosin emulsion, solid content: 50) Mass%, softening point: 85 ° C.) 15 g (solid content 7.5 g) was added, deionized water 11 g was added to adjust the solid content concentration, and the emulsion (16) was stirred at room temperature for 1 hour. Obtained. The physical properties and adhesiveness of the emulsion were measured by the methods described above. The composition and physical properties are shown in Table 4.

Comparative Example 5 (dispersion of emulsifier of tackifier)
Deionized water 188 g, Yasuhara Chemical Co., Ltd. tackifier (“YS Polystar T130”; terpene phenol resin, softening point: 130 ° C.) 50 g, tetrahydrofuran 70 g, isopropyl alcohol 5 g and toluene 5 g were put in an autoclave and heated to 120 ° C. After that, it was heated and dissolved at the same temperature for 2 hours. Next, 5.0 g of an emulsifier manufactured by Dai-ichi Kogyo Co., Ltd. (“DKS NL-180”; polyoxyethylene lauryl ether, HLB: 16.1) was added, and the mixture was further dissolved by heating for 1 hour and then cooled to 40 ° C. . Then, the organic solvent / water was distilled off at a reduced pressure of 91 kPa (absolute pressure), but a tackifier was precipitated during the distillation, and a uniform emulsion could not be obtained.

Comparative Example 6
The emulsion (15) and the pre-emulsion prepared in Comparative Example 5 before distilling off the organic solvent / water were mixed so that the copolymerized polyolefin: tackifier = 100: 15 (mass ratio), An emulsion containing an organic solvent was prepared, but the resin immediately settled.

The tackifiers used in Examples and Comparative Examples are as follows.
YS Polystar (registered trademark) T130: terpene phenol resin, softening point: 130 ° C, manufactured by Yasuhara Chemical Co., Ltd. Alcon (registered trademark) P-90: aliphatic saturated hydrocarbon resin, softening point: 90 ° C, manufactured by Arakawa Chemical Industries, Ltd. Resin (registered trademark) coumarone: coumarone resin, softening point 120 ° C, manufactured by Nikki Chemical Co., Ltd. Hariestar SK-385NS: rosin-based emulsion, softening point 85 ° C, manufactured by Harima Kasei Co., Ltd.

  Since Examples 1 to 12 satisfy claim 1, they show high adhesiveness to both LDPE and HDPE and are excellent in storage stability. In Comparative Example 1, since the ethylene- (meth) acrylic acid ester-maleic anhydride terpolymer was not used, a uniform dispersion could not be obtained. In Comparative Example 2, the acid-modified propylene-ethylene copolymer is used, and although it exhibits adhesiveness to HDPE, it has poor adhesiveness to LDPE. Since Comparative Example 3 does not contain a tackifier, it has poor adhesiveness to LDPE and HDPE. In Comparative Example 4, the tackifier was contained, but since it was not included in the copolymerized polyolefin dispersion particles, the storage stability was poor. In Comparative Example 5, an attempt was made to emulsify the tackifier used in Examples, but a uniform dispersion could not be obtained. In Comparative Example 6, the emulsion of the copolymerized polyolefin and the emulsion of the tackifier were simply mixed, and the tackifier was not included in the copolymerized polyolefin dispersion particles, so that the resin was precipitated and the emulsion was not obtained. .

Since the emulsion of the present invention has excellent adhesiveness to a polyolefin resin substrate, it is useful as a primer for coating, printing, adhering and coating, and as a paint, ink, coating agent and adhesive.

Claims (6)

An emulsion containing a copolymerized polyolefin and a tackifier and satisfying the following (1) to (3).
(1) The copolymerized polyolefin is an ethylene- (meth) acrylate-maleic anhydride terpolymer (2) The copolymerized polyolefin is dispersed in water (3) Dispersion particles made of the copolymerized polyolefin Contains tackifier   The emulsion according to claim 1, wherein the 50% number average particle diameter of the copolyolefin dispersion particles containing the tackifier is more than 100 nm.   The emulsion according to claim 1 or 2, wherein the tackifier is in a range of 5 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the copolymerized polyolefin resin.   An adhesive composition containing the emulsion according to claim 1.   The adhesive composition according to claim 4, which is an adhesive for polyolefin resin.   A method for producing an emulsion, which comprises dissolving a copolymerized polyolefin and a tackifier in a solvent and water, adding a basic substance, and then removing the solvent.