JP7362028B2 - Modified polyolefin resin - Google Patents

Description

The present invention relates to modified polyolefin resins.

In general, polyolefins such as polypropylene and polyethylene are inexpensive and have many excellent properties such as moldability, chemical resistance, water resistance, and electrical properties, so they have been widely used in sheets, films, molded products, etc. in recent years. . However, unlike polar base materials such as polyurethane resins, polyamide resins, acrylic resins, and polyester resins, polyolefin base materials are nonpolar and crystalline, and therefore are difficult to coat or adhere to.

Chlorinated polyolefin resins are widely used as resins that have adhesion to non-polar resin substrates made of polyolefin resins, but chlorinated polyolefin resins have the problem of dehydrochlorination, so polyolefin resins and metals cannot be bonded together. It is considered unsuitable for adhesives such as adhesives, foods, etc. Therefore, for these uses, for example, those based on non-chlorine acid-modified polyolefin resins are generally used (Patent Document 1).

Japanese Patent Application Publication No. 2011-256339

Since these acid-modified polyolefin resins have difficulty in solubility in non-aromatic solvents, they are usually used after being dissolved in an aromatic solvent such as toluene.

However, in recent years, from the viewpoint of environmental issues, there has been a demand for resin compositions using solvents that do not contain aromatic solvents such as toluene.

Therefore, an object of the present invention is to obtain a modified polyolefin resin that can be stably dissolved in solvents other than toluene and has excellent adhesive properties.

As a result of diligent efforts, the inventors of the present application have found that the problems can be solved by the following (1) to (8).
(1) A modified product of component (C) polyolefin resin containing component (A) α,β-unsaturated carboxylic acid or its derivative and component (B) (meth)acrylic acid ester containing at least dodecyl acrylate as a modification component. A modified polyolefin resin that is
A modified polyolefin resin characterized in that the modified polyolefin resin has a melting point measured by a differential scanning calorimeter in the range of 50 to 90°C, and a weight average molecular weight in the range of 20,000 to 250,000.
(2) The modified polyolefin resin according to (1), wherein the component (C) contains a structural unit derived from butene or ethylene in a range of 1 to 25 mol%.
(3) The modified polyolefin resin according to any one of (1) to (2), wherein the component (C) is a propylene-butene copolymer or a propylene-ethylene copolymer. .
(4) A resin composition comprising the modified polyolefin resin according to any one of (1) to (3), and a cycloalkane solvent and a ketone solvent.
(5) A primer comprising the modified polyolefin resin according to any one of (1) to (3) or the resin composition according to (4).
(6) A paint comprising the modified polyolefin resin according to any one of (1) to (3) or the resin composition according to (4).
(7) An ink comprising the modified polyolefin resin according to any one of (1) to (3) or the resin composition according to (4).
(8) An adhesive comprising the modified polyolefin resin according to any one of (1) to (3) or the resin composition according to (4).

In the present invention, it is possible to obtain a modified polyolefin resin that can be stably dissolved in solvents other than toluene and has excellent adhesive properties.

The present invention is directed to modification of component (C) polyolefin resin, which contains component (A) α,β-unsaturated carboxylic acid or its derivative, and component (B) (meth)acrylic acid ester containing at least dodecyl acrylate as a modification component. A modified polyolefin resin that is a product,
The modified polyolefin resin is characterized in that the melting point as measured by a differential scanning calorimeter is in the range of 50 to 90°C, and the weight average molecular weight is in the range of 20,000 to 250,000.

In the present invention, component (A) is an α,β-unsaturated carboxylic acid and/or a derivative thereof. Examples of α, β-unsaturated carboxylic acids and their derivatives include maleic acid, maleic anhydride, fumaric acid, citraconic acid, citraconic anhydride, mesaconic acid, itaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride, Himic anhydride. Examples include acids, (meth)acrylic acid, etc., with maleic anhydride being preferred. Component (B) may be one or more compounds selected from α,β-unsaturated carboxylic acids and derivatives thereof, such as a combination of one or more α,β-unsaturated carboxylic acids and one or more derivatives thereof; It may be a combination of two or more types of α,β-unsaturated carboxylic acids, or a combination of two or more types of derivatives of α,β-unsaturated carboxylic acids.

In addition, in this specification, "(meth)acrylic acid" means methacrylic acid and/or acrylic acid. "(Meth)acrylate" means methacrylate and/or acrylate.

The graft weight of component (A) in the modified polyolefin resin is preferably 0.1% by weight or more, more preferably 0.5% by weight or more when the modified polyolefin resin is 100% by weight. preferable. Thereby, the adhesiveness of the obtained modified polyolefin resin to the metal adherend can be maintained. The upper limit is preferably 10% by weight or less, more preferably 4% by weight or less. This makes it possible to prevent the generation of graft unreacted substances and to obtain sufficient adhesion to the resin adherend. Therefore, the graft weight of component (A) is preferably 0.1% by weight or more and 10% by weight or less, more preferably 0.5% by weight or more and 4% by weight or less.

The graft weight (% by weight) of component (A) can be measured by a known method. For example, it can be determined by alkaline titration.

It is important that component (B) in the present invention contains dodecyl acrylate. The graft weight of component (B) in the modified polyolefin resin is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, based on 100% by weight of the modified polyolefin resin. It is. Thereby, the molecular weight distribution of the modified polyolefin resin can be kept within a sufficiently narrow range. That is, the adverse effects of the high molecular weight portion can be suppressed, and the solvent solubility, low-temperature stability of the solution, and compatibility with other resins can be maintained favorably. Furthermore, the adhesive force can be improved by suppressing the adverse effects of the low molecular weight portion. The upper limit is preferably 10% by weight or less, more preferably 4% by weight or less. Thereby, generation of graft unreacted substances can be suppressed, and adhesion to adherends such as resins and metals can be maintained well. Therefore, the graft weight of component (B) is preferably 0.1% by weight or more and 10% by weight or less, more preferably 0.3% by weight or more and 4% by weight or less.

The graft weight (% by weight) of component (B) can be measured by a known method. For example, it can be determined by alkaline titration.

Although it is important that component (B) contains at least dodecyl acrylate, other (meth)acrylic esters may be appropriately combined as long as the effects of the present invention are not impaired. In addition, when other (meth)acrylic esters are included, as long as the effect of the present invention is not impaired, for example, when the amount of graft modification of the total amount of (meth)acrylic esters is 100%, the graft modification of dodecyl acrylate It is preferable that the amount is 80% or more.

It is preferable that either the graft weight of component (A) or the graft weight of component (B) in the modified polyolefin resin is 0.1% by weight or more and 10% by weight or less, and both are 0.1% by weight. More preferably, the content is 10% by weight or less.

Depending on the use and purpose, graft components (other graft components) other than components (A) and (B) may be used in combination within a range that does not impair the characteristics of the present invention. Examples include (meth)acrylic acid derivatives other than component (A) (eg, N-methyl (meth)acrylamide, hydroxyethyl (meth)acrylamide, (meth)acryloylmorpholine, etc.). The other graft components may be used alone or in combination. The graft weight of other graft components (or their total in the case of a combination of multiple types) is not particularly limited, but preferably does not exceed the total graft weight of components (A) and (B).

Component (C) is a polyolefin resin. The polyolefin resin is not particularly limited as long as it is a polymer of one or more olefin components. Examples of polyolefin resins include homopolymers (such as ethylene or propylene homopolymers) of α-olefins having 2 to 6 carbon atoms; random copolymers and block copolymers of ethylene or propylene and other comonomers. Illustrated. Examples of other comonomers include 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene, with 1-butene being preferred.

Component (C) may be one kind of polyolefin resin, or two or more kinds thereof. As component (C), for example, at least one member selected from the group consisting of ethylene-propylene copolymer, propylene-1-butene copolymer, and ethylene-propylene-1-butene copolymer can be mentioned. , a propylene-1-butene copolymer, or a propylene-1-ethylene copolymer. When the polyolefin resin contains a butene component or an ethylene component, the molar ratio of the butene component or ethylene component is preferably 1 to 25% of the entire polyolefin resin, more preferably 5 to 25%, and even more preferably 10 to 25%. . When the polyolefin resin contains a propylene component, the molar ratio of the propylene component is preferably 40 to 99% of the total polyolefin resin, more preferably 75 to 99%, and still more preferably 75 to 90%.

Note that the butene structural unit content in the polyolefin resin may be the proportion of butene used in the raw material, but may also be calculated by NMR analysis.

The modified polyolefin resin of the present invention can be obtained by graft polymerizing component (A) and component (B) to component (C). Component (D): a radical generator may be used during production.

The radical generator may be a known radical generator, and organic peroxide compounds are preferred. Examples of organic peroxide compounds include di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, dilauryl peroxide, cumene hydroperoxide, and t-butyl hydroperoxide. , 1,4-bis[(t-butylperoxy)isopropyl]benzene, 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, oxy)-cyclohexane, cyclohexanone peroxide, t-butylperoxybenzoate, t-butylperoxyisobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxy-2- Examples include ethylhexanoate, t-butyl peroxyisopropyl carbonate, cumyl peroxy octoate, etc., di-t-butyl peroxide, dicumyl peroxide and dilauryl peroxide are preferred, and dilauryl peroxide is more preferred. . Component (D) may be a single radical generator or a combination of multiple types of radical generators.

As a method for producing a modified polyolefin resin using component (D), for example, a mixture of components (A), (B) and (C) is heated and dissolved in an organic solvent such as toluene or xylene, and component (D) is dissolved in an organic solvent such as toluene or xylene. ), or by adding components (A), (B), (C), and (D) using a kneading machine such as a Banbury mixer, kneader, or extruder, and melt-kneading reaction under heating. A method for obtaining a modified polyolefin resin can be mentioned. In the production of a modified polyolefin resin, components (A), (B), (C), and (D) may be added to the reaction system all at once or sequentially.

The amount of component (D) added in the graft polymerization reaction is preferably 1% by weight, more preferably 10% by weight, based on the total (weight) of the amount of component (A) and the amount of component (B) added. Weight%. Thereby, sufficient grafting efficiency can be maintained. The upper limit is preferably 100% by weight or less, more preferably 50% by weight or less. Thereby, a decrease in the weight average molecular weight of the modified polyolefin resin can be suppressed.

It is important that the melting point (Tm) of the modified polyolefin resin of the present invention thus obtained is in the range of 50 to 90°C, preferably in the range of 60 to 90°C, and preferably in the range of 60 to 80°C. The temperature is more preferably in the range of 60 to 75°C.

Note that the melting point can be measured by differential scanning calorimetry (DSC) or the like.

The measurement of Tm by DSC in the present invention can be performed, for example, under the following conditions. In accordance with JIS K7121-1987, using a DSC measuring device (DISCOVERY DSC2500 manufactured by TA Instruments Japan), approximately 5 mg of the sample was heated at 150°C for 10 minutes, kept in a molten state, and then heated at 10°C/min. After lowering the temperature at a rate of 10° C. and stably maintaining it at −50° C., the temperature is further increased to 150° C. at a rate of 10° C./min to measure the melting peak temperature, and this temperature is evaluated as Tm. Incidentally, Tm in the examples described below was measured under the conditions described above.

It is important that the weight average molecular weight of the modified polyolefin resin of the present invention is in the range of 20,000 to 250,000, preferably 40,000 to 200,000, 50,000 to 180, More preferably, it is in the range of 000.

Note that the weight average molecular weight is a value based on a polystyrene resin measured by gel permeation chromatography (GPC).

The modified polyolefin resin of the present invention is graft-modified with a specific (meth)acrylic acid ester, and the melting point and weight average molecular weight of the modified polyolefin resin are within the above-mentioned specific ranges. It can be effective.

The modified polyolefin resin of the present invention can be made into a resin composition dispersed in a solvent. As a solvent, aromatic solvents (toluene, xylene, etc.); alicyclic hydrocarbon solvents (cycloalkanes such as cyclohexane, methylcyclohexane, etc.); aliphatic hydrocarbon solvents (hexane, heptane, octane, etc.); ketone solvents (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); ester solvents (methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, etc.) glycol solvents (ethylene glycol, ethyl cellosolve, butyl cellosolve, etc.) ); alcoholic solvents (methanol, ethanol, n-butanol, t-butanol, etc.); and mixed solvents thereof; examples include alicyclic hydrocarbon solvents (preferably (methyl)cyclohexane, etc.) and ketones. A mixed solvent of type solvents (such as methyl ethyl ketone) is preferable. The weight ratio of each solvent in the mixed solvent is not particularly limited, but in the case of aromatic solvent/alicyclic hydrocarbon solvent, it is preferably 9/1 to 5/5, and more preferably 8/2 to 6/4. preferable.

The resin composition containing the modified polyolefin resin of the present invention may be further used in combination with other components. Examples of such other components include a curing agent and an adhesive component.

Examples of the curing agent include polyisocyanate compounds, epoxy compounds, polyamine compounds such as isophorone diamine, polyol compounds, and crosslinking agents whose functional groups are blocked with protective groups. The curing agent may be used alone or in combination. The blending amount of the curing agent can be appropriately selected depending on the content of component (A) in the modified polyolefin resin of the present invention. When the composition of the present invention contains a curing agent, it may also contain a catalyst. Examples of the catalyst include organic tin compounds and tertiary amine compounds, and an appropriate one may be selected from these depending on the purpose.

Examples of adhesive components include known adhesives such as polyester adhesives, polyurethane adhesives, and acrylic adhesives.

The modified polyolefin resin of the present invention not only has excellent adhesion but also excellent stability in solution, so it can be used as an adhesive, a primer, a paint binder, and an ink binder.

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

(Example 1)
100 parts by weight of propylene-ethylene copolymer (89 mol% propylene component, 11 mol% ethylene component, weight average molecular weight 50,000, Tm=65°C), 4.0 parts by weight maleic anhydride, 2.5 parts by weight dodecyl acrylate 1 part by weight of dilauryl peroxide were kneaded and reacted using a twin screw extruder set at 170°C. Degassing was carried out under reduced pressure in the extruder to remove remaining unreacted materials, and the weight average molecular weight was 55,000, Tm = 64°C, the graft weight of maleic anhydride was 3.4% by weight, and the graft weight of dodecyl acrylate. A modified polyolefin resin 1 containing 2.0% by weight was obtained.

(Example 2)
In a four-necked flask equipped with a stirrer, condenser, and dropping funnel, propylene-ethylene copolymer (propylene component 88 mol%, ethylene component 12 mol%, weight average molecular weight 200,000, Tm = 60 ° C.) 100 After heating and dissolving the weight part in 400 g of toluene, while maintaining the temperature in the system at 110°C and stirring, 4.5 parts of maleic anhydride, 3.5 parts of dodecyl acrylate, and di-t-butyl peroxide were added. One part of each was added dropwise over 3 hours, and the reaction was further allowed to proceed for 1 hour.

After the reaction is completed, the reaction product is cooled to room temperature and purified by pouring it into a large excess of acetone, resulting in a weight average molecular weight of 130,000, Tm = 60°C, and a graft weight of maleic anhydride of 3.0 weight. %, and a modified polyolefin resin having a graft weight of dodecyl acrylate of 2.0% by weight was obtained.

(Example 3)
In a four-necked flask equipped with a stirrer, condenser, and dropping funnel, propylene-ethylene copolymer (propylene component 88 mol%, ethylene component 12 mol%, weight average molecular weight 200,000, Tm = 60 ° C.) 100 After heating and dissolving the weight part in 400 g of toluene, 1.0 part of maleic anhydride, 1.0 part of dodecyl acrylate, and di-t-butyl peroxide were added while maintaining the temperature in the system at 110°C and stirring. 0.4 part of each was added dropwise over 3 hours, and the reaction was further allowed to proceed for 1 hour.

After the reaction is completed, the reaction product is cooled to room temperature and purified by pouring it into a large excess of acetone, resulting in a weight average molecular weight of 120,000, Tm = 60°C, and a graft weight of maleic anhydride of 0.8 weight. %, and a modified polyolefin resin having a graft weight of dodecyl acrylate of 0.6% by weight was obtained.

(Example 4)
100 parts by weight of propylene-1-butene copolymer (propylene component 70 mol%, butene component 30 mol%, weight average molecular weight 250,000, Tm=75°C), 2.5 parts by weight maleic anhydride, 2.5 parts by weight dodecyl acrylate. 0 parts by weight and 1 part by weight of dilauryl peroxide were kneaded and reacted using a twin screw extruder set at 175°C. Perform vacuum degassing in the extruder,
Remaining unreacted materials were removed to obtain a modified polyolefin resin with a weight average molecular weight of 150,000, Tm = 73°C, a graft weight of maleic anhydride of 1.6% by weight, and a graft weight of dodecyl acrylate of 1.3% by weight. I got 1.

<Evaluation>
(Evaluation test)
The modified polyolefin resins obtained in Examples and Comparative Examples were dissolved in a methylcyclohexane/methyl ethyl ketone solution (mixing ratio 80/20) in a glass bottle to prepare a coating composition with a concentration of 15% by mass. Table 1 shows the results of performance evaluation of the obtained coating composition according to the following procedure.

<Adhesion test>
In the heat seal strength test, the coating composition was applied as an adhesive onto aluminum foil using a #16 Meyer bar so that the dry resin film thickness was 3 μm, and then dried at 180° C. for 10 seconds. The coated aluminum foil was laminated with an unstretched polypropylene (CCP) film, and thermocompression bonding was performed at 200° C. for 1 second at 100 kPa to prepare a test piece cut out to a width of 15 mm. After storing the test piece at constant temperature and humidity for 24 hours at 23° C. and 50% relative humidity, the laminate adhesive strength was measured under conditions of peeling in a 180 degree direction and a peeling rate of 100 mm/min, and evaluated using the following criteria.
〇: Adhesive strength is 8 N/15 mm or more, good adhesion.
×: Adhesive strength is less than 8 N/15 mm, and adhesiveness is poor.

<Solution stability test>
200 ml of the coating composition obtained as described above was placed in a 225 ml glass bottle, tightly sealed to prevent the solvent from volatilizing, and left to stand at room temperature (23°C) for one week, after which the stability of the solution was visually observed. Evaluation was made using the following evaluation criteria.
○: The coating composition remains transparent and fluidity is maintained.
×: The coating composition is cloudy and has decreased fluidity.

Claims (8)

Modified component (C) is a modified polyolefin resin containing component (A) α,β-unsaturated carboxylic acid or its derivative and component (B) (meth)acrylic acid ester containing at least dodecyl acrylate as a modified component. A modified polyolefin resin, characterized in that the modified polyolefin resin has a melting point in the range of 60 to 75 °C as measured by a differential scanning calorimeter, and a weight average molecular weight in the range of 50,000 to 180,000. resin.
The modified polyolefin resin according to claim 1, wherein the component (C) contains a structural unit derived from butene or ethylene in a range of 1 to 25 mol%. The modified polyolefin resin according to any one of claims 1 to 2, wherein the component (C) is a propylene-butene copolymer or a propylene-ethylene copolymer. A resin composition comprising the modified polyolefin resin according to any one of claims 1 to 3, and a cycloalkane solvent and a ketone solvent. A primer comprising the modified polyolefin resin according to any one of claims 1 to 3 or the resin composition according to claim 4. A paint comprising the modified polyolefin resin according to any one of claims 1 to 3 or the resin composition according to claim 4. An ink comprising the modified polyolefin resin according to any one of claims 1 to 3 or the resin composition according to claim 4. An adhesive comprising the modified polyolefin resin according to any one of claims 1 to 3 or the resin composition according to claim 4.