JPH03182513A - Production of modified ethylene polymer - Google Patents

Abstract

PURPOSE:To obtain a modified ethylene polymer excellent in adhesion to a polyurethane coating material or adhesive or the like by treating an ethylene/ unsaturated carboxylic ester copolymer, an organic compound having a double bond and an OH group and an organic peroxide in a specified ratio at a specified temperature. CONSTITUTION:100 pts. wt. ethylene/unsaturated carboxylic ester copolymer of an unsaturated carboxylic ester content of 3-50wt.% (e.g. ethylene/methyl acrylate copolymer), 0.1-20 pts.wt. organic compound having one double bond and one hydroxyl group (e.g. 2-hydroxyethyl acrylate) and 0.01-10 pts.wt. organic peroxide (e.g. dicumyl peroxide) are mixed together and heated to 60-250 deg.C to obtain a modified ethylene polymer.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing a modified ethylene polymer that has excellent adhesion to polyurethane. More specifically, the present invention relates to a method for producing a modified ethylene polymer that has good adhesion to polyurethane. [Conventional technology 1] As is well known, polyolefin resins (polypropylene resins, polyethylene resins) not only have excellent moldability, but also have excellent mechanical properties, heat resistance, solvent resistance, oil resistance, and chemical resistance. Because of their excellent properties, they are widely manufactured industrially and used in a wide variety of applications, including parts and packaging materials for automobiles, electrical appliances, and electronic devices, various containers, and other daily necessities. However, since it does not have a polar group in its molecule (it is so-called inert), it has poor adhesion to various substances. In particular, we will explain the adhesion with polyurethane resin. Currently, exterior parts such as bumpers and bumper corners of automobiles are made of propylene-based polymers containing propylene as the main component, as well as ethylene-propylene copolymer rubber and inorganic fillers, in order to reduce the weight and cost of automobiles. Mainly, a composition containing talc) is molded, and the molded product is subjected to electrical treatment (e.g., corona discharge treatment, plasma treatment),
The surface is subjected to surface treatments such as 111d roughening, flame treatment, and oxygen or ozone treatment, undercoated with a propylene-based polymer and a brimer with good adhesion, and then coated with a polyurethane-based paint. However, in the process of applying this brimer, generally after applying the brimer, the brimer is completely adhered (baked). This process requires a long time (usually about 40 to 80 minutes). Moreover, in order to carry out the double coating process, it is necessary to use a large amount of an organic solvent (for example, toluene) as a solvent for the brimer, which poses problems in terms of working environment and air pollution. In addition, by taking advantage of the insulation and cushioning properties of polyurethane foam, it is used as a cushioning material for interior parts of automobiles such as instrument panels, armrests, and seat backs, as well as for home appliances such as electric refrigerators and air conditioners, and refrigerated trucks. Used as a heat insulator. When polyurethane foam is used in such fields, it is often necessary that the polyurethane foam be firmly adhered to the base material or surface material of the product. By the way, when the base material or surface material has high surface activity such as metal, wood, or ABS resin (acrylonitrile-butadiene-styrene ternary copolymer resin),
Due to its excellent adhesion to polyurethane foam,
If the urethane polymer formation reaction and foaming are performed simultaneously on a substrate using a method such as injection foaming used in the production of polyurethane foam, a product (laminate) with strong adhesion can be obtained. However, as mentioned above, it is impossible to manufacture a laminate with polyurethane foam using an inert polyolefin resin as a base material or surface material because the adhesiveness is extremely low. For this reason, when a polyolefin resin and a polyurethane foam are brought into close contact with each other, a brimer must be applied in advance to the surface of the polyolefin resin molded product as described above. For these reasons, polyolefin resins have at least one unsaturated bond in their molecules and organic compounds containing hydroxyl groups (hereinafter referred to as "hydroxyl compounds").
It has been proposed to improve the adhesion of polyurethane paints and polyurethane foams by treating them with at least an organic peroxide (for example, Japanese Patent Application Laid-open Nos. 154732-1982, 191706-1980, and 1987-19170). 58-185344, 61-272417). Among polyolefin resins, modified products obtained by treating propylene polymers (polypropylene resins) in the same manner as above, crystalline ethylene-propylene block copolymers, amorphous ethylene-propylene copolymers, Compositions with inorganic fillers etc. not only have excellent adhesion to polyurethane without applying a brimer, but also have good flexural modulus and impact resistance at low temperatures, as well as processability and moldability. It has also been proposed in the past to be molded to be suitable for automobile exterior parts such as bumpers.
No. 2-209150, No. 62-207344, No. 62
-257945). Furthermore, compositions of the above-mentioned modified products and crystalline ethylene-propylene block copolymers, ethylene-vinyl acetate copolymers, etc. can be used at room temperature with chloroprene-based two-component solvent adhesives without the need for applying a brimer. Not only does it have good adhesion, it also has excellent adhesion even at temperatures of 80°C, and it also has good flexural modulus and impact resistance, making it suitable for automobile interior parts (e.g. door liners). As previously proposed (Unexamined Japanese Patent Publication No. 6
No. 4-29446, No. 64-36636, No. 64-4
No. 5446, No. 64-48842, No. 64-7294
No. 6). [Problems to be Solved by the Invention] A modified product obtained by treating a polyolefin resin such as the polypropylene resin with at least a hydroxyl compound and an organic peroxide improves the adhesion to a polyurethane paint or polyurethane foam. It can be improved. However, in practical terms, the adhesion is not necessarily sufficient. In particular, the modified product may be added to the above-mentioned polypropylene resins (e.g. propylene homopolymer,
As mentioned above, when a composition with a crystalline ethylene-propylene block copolymer (crystalline ethylene-propylene block copolymer) etc. is molded into the exterior or interior parts of an automobile, and a polyurethane paint or polychloroprene adhesive is applied without applying a primer, The adhesion with these materials is not always sufficient and there are problems in use. From these facts, the present invention has extremely good adhesion to polyurethane paints and polyurethane foams even without the use of a brimer, and can be applied to polypropylene resins such as ethylene-propylene block copolymers or polypropylene resins. When mixed with amorphous ethylene-propylene copolymer rubber, etc., not only does it have excellent adhesion to polyurethane paints and polyurethane foam without the use of a brimer, but it also improves flexural modulus (rigidity) and impact resistance. It has good mechanical properties such as
Moreover, it is an object of the present invention to produce a modified ethylene polymer that has excellent moldability and processability and can be used as a composition suitable for the exterior and interior parts of automobiles. [Means and effects for solving the problems] According to the present invention, these problems are solved by (ethylene-unsaturated carboxylic acid having a copolymerization ratio of 3.0 to 50% by weight of Al-unsaturated carboxylic ester) Ester copolymer 100 parts by weight (B) 0.1 to 20 parts by weight of an organic compound having one double bond and one hydroxyl group (i.e. hydroxyl compound) and (C) organic peroxide 60-2 parts by weight of 0.01-10 parts by weight
The problem can be solved by a method for producing a modified ethylene polymer, which is characterized by processing at 50°C. The present invention will be specifically explained below. (A) Ethylene-unsaturated carboxylic ester copolymer The ethylene-unsaturated carboxylic ester copolymer used in the present invention is a copolymer of at least ethylene and an unsaturated carboxylic ester (a third comonomer). (including multi-component copolymers with). The copolymerization ratio of the unsaturated carboxylic ester in the ethylene-unsaturated carboxylic ester copolymer is 3.0 to 50% by weight, and 4.0 to 50% by weight.
The amount is preferably 45% by weight, particularly preferably 5.0 to 40 parts by weight. The copolymerization ratio of unsaturated carboxylic acid ester is 3.
If a 0% by weight ungrooved ethylene-unsaturated carboxylic acid ester copolymer is used, the adhesion to polyurethane paints and polyurethane foams will be low. On the other hand, when the ethylene-unsaturated carboxylic acid ester copolymer is used in an amount exceeding 50 parts by weight, the physical properties of the modified product and the composition when the composition is produced are deteriorated. The melt flow index (JIS
K7210, measured under conditions 4 in Table 1, hereinafter referred to as rMFRJ), is generally 0.5 to 300.
g/10 minutes, preferably 0.5 to 200 g/10 minutes, particularly preferably 0.5 to 150 g/10 minutes. Ethylene with MFR less than 0.5g/10min
If an unsaturated carboxylic acid ester copolymer is used,
Not only is the kneading property poor, but when the resulting modified product is used to produce a composition with a polypropylene resin, etc., the kneading property and moldability of the composition are poor. On the other hand, 300g/1
If the ethylene-unsaturated carboxylic acid ester copolymer is used for more than 0 minutes, the mechanical strength will be poor. The unsaturated carboxylic acid ester usually has 4 to 40 carbon atoms, particularly preferably 4 to 20 carbon atoms. A typical example of an unsaturated carboxylic acid ester is methyl (
Mention may be made of meth)acrylate and ethyl (meth)acrylate and alkoxyalkyl (meth)acrylate. The alkoxy group of the alkoxyalkyl (meth)acrylate has 1 to 8 carbon atoms (preferably 1 to 4 carbon atoms)
) and the alkyl group has 1 to 8 carbon atoms (preferably 1 to 4 carbon atoms). Representative examples of suitable alkoxyalkyl (meth)acrylates include: Mention may be made of methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate and butoxyethyl (meth)acrylate. In addition, the third comonomer may have at most 20 carbon atoms.
(preferably 4 to 16). Typical examples include vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl bivalate. The copolymerization proportion of the third comonomer is usually at most 10% by weight, preferably 5.0% by weight or less. (8) Hydroxyl Compound The hydroxyl compound used in the present invention is an organic compound having one double bond and a hydroxyl group. The general formula of the hydroxyl compound is usually represented by the following formula [(■) formula]. In formula (1), R1 is a hydrogen atom or has 1 to 1 carbon atoms.
There are 6 alkyl groups. Furthermore, R2 has 1 to 2 carbon atoms.
0 alkylene groups. In formula (1), R8 is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and particularly preferably a hydrogen atom, a methyl group, or an ethyl group. Further, R is preferably an alkylene group having 1 to 6 carbon atoms, and particularly preferably an alkylene group having 1 to 4 carbon atoms. Suitable hydroxyl compounds include 2-hydroxy-ethyl-methacrylate, 2-hydroxy-ethyl-methacrylate, and 2-hydroxy-ethyl-methacrylate.
Mention may be made of acrylate, 2-hydroxy-propyl-methacrylate and 2-hydroxy-methyl-methacrylate. (C1 organic peroxide) Furthermore, the organic peroxide used in the present invention is generally used as an initiator in radical polymerization and a crosslinking agent for polymers, and has a half-life of 1 minute.
A temperature of 110°C or higher is preferred, and a temperature of 110°C or higher is particularly preferred. If the above temperature is less than 100℃,
Not only is it difficult to handle, but the effects of using it are not very noticeable, so it is not desirable. Representative examples of preferred organic peroxides include ketone peroxides such as 1,1-bis-tertiary-butylperoxy-3,3,5-trimethylcyclohexane, dialkyl peroxides such as dicumyl peroxide, Hydroperoxides such as .5-dimethylhexane-2,5-hydroperoxide, diacylperoxides such as benzoyl peroxide and peroxyesters such as 2,5-dimethyl-2,5-dibenzoylperoxyhexane are mentioned. It will be done. (Dl usage ratio In producing the modified ethylene polymer of the present invention,
The ratio of the hydroxyl compound and organic peroxide to 100 parts by weight of the ethylene-unsaturated carboxylic acid ester copolymer is as follows. The proportion of the hydroxyl compound used is 0.1 to 20 parts by weight, preferably 0.1 to 15 parts by weight, particularly 0.2 to 20 parts by weight.
15 parts by weight is preferred. If the proportion of the hydroxyl compound used is less than 0.1 parts by weight, the effect of improving adhesion is insufficient. On the other hand, if the amount exceeds 20 parts by weight, the effect of improving adhesion depending on the amount used will not be observed, but rather the original properties of the ethylene-unsaturated carboxylic acid ester copolymer will be impaired, or unreacted hydroxyl This is undesirable because the compound remains in the resulting modified ethylene polymer. In addition, the usage ratio of organic peroxide is 0. 10 parts by weight, preferably 0.02 to 10 parts by weight, especially 0,
05 to 7.0 parts by weight is suitable. The usage ratio of organic peroxide is 0. If the amount is less than 10 parts by weight, the effect of improving adhesion is low; on the other hand, even if it exceeds 10 parts by weight, not only will the adhesion not be further improved, but the ethylene-
The unsaturated carboxylic acid ester copolymer itself may cause crosslinking, which is undesirable. (El treatment method In order to produce the modified ethylene polymer of the present invention, the above-mentioned ethylene-unsaturated carboxylic acid ester copolymer, hydroxyl compound and organic peroxide are used in the above-mentioned proportions in a conventional modified olefin-based polymer. When producing a polymer, this can be achieved by processing it by employing any of the commonly used known methods (for example, solution method, suspension method, melt method). Modification by solution method When producing ethylene polymers,
Adding an ethylene-unsaturated carboxylic acid ester copolymer and a hydroxyl compound to an inert organic solvent,
It can be produced by further adding an organic peroxide and stirring sufficiently in the temperature range shown below. Examples of the inert organic solvent include hexane, heptane, toluene, xylene, and chlorobenzene. In this solution method, the treatment temperature varies depending on the type of organic peroxide and the type of ethylene-unsaturated carboxylic acid ester copolymer, but is generally 60 to 120°C, particularly preferably 70 to 110°C. In addition, when producing modified ethylene polymers by the suspension method,
Although it varies depending on the type of the ethylene-unsaturated carboxylic acid ester copolymer in the aqueous suspension, the treatment temperature is usually 60 to 100°C. In both the solution method and the suspension method, if the treatment temperature is below the lower limit, the treatment takes a long time, which poses an industrial problem. On the other hand, if the upper limit is exceeded, although the processing time is shortened, a rapid reaction occurs, making it difficult to carry out the processing and making it difficult to obtain a good modified product. In any of the above cases, not only is the treatment time long, but post-treatment such as drying is required to completely remove the organic solvent and water used after treatment. be. This poses a cost problem. In contrast to these methods, the melting method, which requires a short processing time and does not require post-processing, is industrially desirable. When producing modified ethylene polymers by the melt method, kneading methods such as Banbury mixers, kneaders, roll mills, and screw extruders (especially screw extruders) commonly used in the field of general synthetic resins are used. (preferable because of its simplicity) can be produced by melt-kneading. At this time, a more uniform modified ethylene polymer can be produced by tri-blending in advance using a mixer such as a Henschel mixer, and then melt-kneading the resulting mixture, or by performing melt-mixing two or more times. can. Melt kneading must be carried out at a temperature at which the organic peroxide used is decomposed. However, it goes without saying that the ethylene-unsaturated carboxylic acid ester copolymer used must not deteriorate and the treatment must be carried out at a temperature that can be controlled. For these reasons, the processing temperature is generally 10
The temperature is 0 to 250°C, particularly preferably 120 to 230°C. fF) Molding method The modified ethylene polymer thus obtained is generally used in the field of polyolefin resins depending on the purpose of use, when producing the desired molded product by the molding method described below. such as oxygen, heat and UV stabilizers, metal deterioration inhibitors, flame retardants, colorants, electrical property modifiers, fillers, antistatic agents, lubricants, processability modifiers and tack modifiers. Additives may be mixed as long as they do not impair the properties of the modified ethylene polymer of the present invention. Furthermore, the mechanical strength, moldability,
Synthetic resins or rubbers that can improve processability and are compatible with the modified ethylene polymer may be blended. This synthetic resin, which may be blended within a range that does not practically impair adhesion, includes low-density polyethylene resin, medium to high-density polyethylene resin, linear low-density polyethylene resin, propylene homopolymer, and propylene as a main component. A random copolymer with ethylene and/or an α-olefin having 4 to 12 carbon atoms,
A polymer obtained by block copolymerizing propylene as the main component with a small amount of ethylene, and a polymer obtained by block copolymerizing propylene with a small amount of ethylene. , its derivatives, vinyl esters, unsaturated carboxylic acid esters)
Examples include copolymers with Examples of the rubber include amorphous ethylene-propylene copolymer rubber, low-crystalline ethylene-propylene copolymer, and rubber containing butadiene as a main component. Furthermore, the rigidity can be improved by adding a filler that is generally blended into synthetic resins and rubbers. The modified ethylene polymer of the present invention or the above synthetic resin,
A desired molded article can be produced from a composition containing rubber, additives, etc. by a molding method commonly used in the field of olefin resins. Examples of the molding method include injection molding, extrusion molding, blow molding, stamping molding, compression molding, and vacuum molding. A molded product whose surface is coated with polyurethane can be obtained by applying a polyurethane paint to the molded product thus obtained using a commonly used method. Further, in order to adhere closely to the polyurethane foam, the urethane polymer formation reaction and foaming may be simultaneously performed on the surface of the molded product obtained as described above. In order to achieve close contact, no special equipment or special method is required. That is, it is sufficient to apply foaming methods such as injection foaming, mold foaming, and spray foaming that are commonly used in the field of polyurethane foam manufacturing. The agent does not need to be special, and any commonly used agent may be used without any limitation.

[Effect]

Although the mechanism of the development of adhesiveness between the modified ethylene polymer obtained by the method of the present invention and polyurethane is not clear, it is presumed to be due to the following mechanism of action. In the modified ethylene polymer obtained by the method of the present invention, a hydroxyl compound is bonded to the ethylene-vinyl acetate copolymer by the above treatment, and the hydroxyl group (-OH) of the compound is bonded to the isocyanate group of the polyurethane. As a result, strong adhesion is developed between, for example, a polyurethane paint and a molded article of a modified ethylene polymer. In addition, ethylene-unsaturated carboxylic acid ester copolymers have superior wettability compared to polyolefin resins that do not have polar groups, such as polyethylene resins and polypropylene resins, so they can be used, for example, in polyurethane paints. The compound having an isocyanate group easily approaches the surface of the copolymer, and the rate of reaction between the isocyanate group and the hydroxyl group increases, resulting in stronger adhesion.

[Example and Comparative Example J] Hereinafter, the present invention will be explained in more detail with reference to Examples. In addition, in the Examples and Comparative Examples, the adhesion strength of the coating film was determined by making a 1 cm wide line on a molded flat plate and pulling at a tensile speed of 50 m.
It was determined by measuring the 180°C peel strength of the coating film under conditions of 1/min. In addition, the ethylene-
The physical properties of the unsaturated carboxylic acid ester copolymer, hydroxyl compound, organic peroxide, and low density polyethylene resin used for comparison are shown below. [(A) Ethylene-unsaturated carboxylic acid ester copolymer] As an ethylene-unsaturated carboxylic acid ester copolymer, the copolymerization ratio of ethyl acrylate is 11% by weight, and the MFR is 20 g/10 minutes. A certain ethylene-ethyl acrylate copolymer [hereinafter referred to as "EEA (1)"]
The copolymerization ratio of ethyl acrylate is 23% by weight,
Ethylene-ethyl acrylate copolymer [hereinafter referred to as rEEA (21J) 1, which has an MFR of 24 g/10 minutes, a copolymerization ratio of methyl methacrylate of 9.0% by weight, and an MFR of 18 g/10 minutes. A certain ethylene-methyl methacrylate copolymer [hereinafter referred to as rEMM]
The copolymerization ratio of Ii5 and methyl methacrylate is 20% by weight, and the MFR is 21 g.
/10 minutes, an ethylene-methyl methacrylate copolymer [EMMA (referred to as blJ) was used. [(B) Hydroxyl compound] In addition, as a hydroxyl compound, 2-hydroxyl-ethyl-methacrylate (hereinafter referred to as rHEMAJ)
It was used. [(C) Organic Peroxide J Furthermore, dicumyl peroxide (hereinafter referred to as rDCPJ) was used as an organic peroxide. [(D) Low-density polyethylene resin, etc. For comparison,
As a low-density polyethylene resin, a low-density ethylene homopolymer (hereinafter referred to as rLDPEJ) manufactured by a so-called high-pressure method and having a density of 9 x 7 g/cm' and an MFR of 7.2 g 710 minutes, and a polypropylene resin, Melt flow index (according to JIS K7210, measured under conditions 14 in Table 1) is 8.0 g 7
A propylene homopolymer (hereinafter referred to as rPPJ) having a 10-min. Examples 1 to 10, Comparative Examples 1 to 5 Ethylene-unsaturated carboxylic acid ester copolymer, low density polyethylene resin (LDPE), propylene homopolymer (pp )
HEMA (2-hydroxyl-ethyl-methacrylate, as a hydroxyl compound) and DCP (2-hydroxyl-ethyl-methacrylate, as a hydroxyl compound) and DCP (
Dicumyl peroxide (as an organic peroxide) was tri-blended for 10 minutes using a super mixer. Each of the obtained mixtures was mixed into pellets at 180° C. using a vented twin-screw extruder (diameter 40 m5+) to produce pellets. Each of the obtained pellets was injection molded at a resin temperature of 160 to 170°C (210°C in the case of PP), and a flat specimen (
2mm thick, 120mm x 120mm). A two-component polyurethane paint (manufactured by Nippon B Chemical Co., Ltd., trade name: R271,
Pure White) was sprayed evenly using a spray gun. Then, it was heated and dried at a temperature of 60° C. for 90 minutes. The coating film adhesion strength of each specimen thus obtained was measured. The results are shown in Table 1. Table [Effects of the Invention] The modified ethylene polymer obtained by the method of the present invention has excellent adhesion to polyurethane paints even without the use of a brimer, and also has excellent adhesion to polyurethane adhesives and polyurethane foam. The quality is also good. Furthermore, by molding the composition obtained by blending these with various polyolefin polymers that have poor adhesion, and omitting steps such as coating and drying the resulting molded product, productivity can be improved. It is thought that the adhesion of the system to paints, adhesives and foams can be significantly improved. The modified ethylene polymer obtained by the method of the present invention and the composition containing the modified ethylene polymer can be used in a wide variety of fields to exhibit the above-mentioned effects. bumper,
Examples include exterior parts such as bumper corners, interior parts such as instrument panels and door liners, and motorcycle parts such as fenders. Procedural amendment (voluntary) ■, Indication of the case 1999 Patent Application No. 321915 2, Name of the invention Process for producing modified ethylene polymer 3, Person making the amendment Relationship with the case Patent applicant address Minato-ku, Tokyo Shiba Daimon-chome 13-9 Address No. 9-5 Showa Denko K.K., Shiba Daimon-chome 13-chome, Minato-ku, Tokyo, ``Detailed Description of the Invention'' column of the specification to be amended. 6. Contents of the amendment (1) The text "I will explain." on page 2, line 11 of the specification will be amended to "I will explain." (2) On page 5, lines 16 and 17, the words "previously" will be amended to read "previously." (3) On page 6, line 8 of the same document, the phrase "previously" has been amended to read "previously." (4) On page 16, line 7 of the same document, the word "alterative" has been amended to read "substantive." (5) On page 24, line 15 of the same, "Nippon B Chemical" has been corrected to "Nippon B Chemical."

Claims (1)

[Claims] (A) Copolymerization ratio of unsaturated carboxylic acid ester is 3.0
100 parts by weight of an ethylene-unsaturated carboxylic acid ester copolymer of ~50% by weight (B) 0.1 to 20 parts by weight of an organic compound having one double bond and one hydroxyl group, and (C) A method for producing a modified ethylene polymer, which comprises treating 0.01 to 10 parts by weight of an organic peroxide at 60 to 250°C.