KR19990054418A - Method of Making Adhesive Polyethylene-Elastomer Blend - Google Patents

Abstract

According to the present invention, a mixture is prepared by mixing 1-20 phr of maleic anhydride, 1-10 phr of acrylic acid, and an initiator in a mixture of polyethylene and an elastomer at 110-150 ° C., and then grafting the temperature to 150-200 ° C. The present invention relates to a method for producing a polyethylene-elastic blend, which is capable of producing a blend of polyethylene-elastomer with excellent adhesion, high mechanical strength, fluidity, coating processability, and resistance to natural environmental exposure. It has an effect.

Description

Method of Making Adhesive Polyethylene-Elastomer Blend

The present invention relates to a method for producing an adhesive polyethylene-elastomer blend, and more particularly, an adhesive polyethylene-elastomer blend having excellent adhesive properties by grafting maleic anhydride and acrylic acid to a mixture of polyethylene and an elastomer. It relates to a method of manufacturing.

Polyethylene (polyethylene) has excellent corrosion resistance and flexibility has been attempted to use a protective coating material such as steel, ceramics using these properties of polyethylene. However, ordinary polyethylene has little adhesion and is not suitable for use as a coating material without proper modification.

As a method for increasing the adhesive strength of polyethylene, a method of making a copolymer with acrylic acid (AA) and the like, a method of blending a polymer having high adhesion with the coating material and having compatibility with polyethylene, acrylic acid, male Grafting of maleic anhydride (MAH) on polyethylene (graft) to produce a copolymer (grafted copolymer) such monomers are mainly used.

A method of preparing an ethylene-acrylic acid copolymer or an ethylene-maleic anhydride copolymer by polymerizing monomers such as acrylic acid and maleic anhydride together with ethylene has a disadvantage that high pressure and temperature are required in order for the polymerization reaction of ethylene and monomer to occur. .

The method of grafting molecules such as maleic anhydride or acrylic acid to polyethylene is characterized by the fact that it is possible to make modified polyethylene in a short time by simple equipment.

Adhesive polyethylene is not only excellent in corrosion resistance and flexibility, but also good in adhesiveness, and then mixed with pigments, thermal stabilizers and ultraviolet stabilizers, and then made into powder, which can be directly used as a protective coating material for steel and ceramics.

However, the conventional adhesive polyethylene has a problem that the coating film cracks or splits when exposed to the natural environment for a long time, which is a very fatal defect when used as a coating material of the equipment that is operated by exposure to heat or sunlight for a long time.

As a method for solving the above problems, a method of mixing an elastomer with an adhesive polyethylene is used.

However, when an elastomer such as ethylene propylene rubber (hereinafter referred to as "EPR") is mixed with the adhesive polyethylene, there is a problem in that the adhesive strength of the adhesive polyethylene decreases in proportion to the content of the mixed EPR.

In particular, when 40-90% by weight of EPR is added to the adhesive polyethylene, the adhesive strength of the adhesive polyethylene is reduced to about 2-20% of the pure adhesive polyethylene.

In order to solve the above problems, the present invention provides excellent adhesion and high mechanical strength through a process of grafting maleic anhydride and acrylic acid to a mixture of polyethylene and an elastomer, instead of mixing an elastomer with an adhesive polyethylene. It is an object of the present invention to provide a method for producing a blend of polyethylene-elastomer that is excellent in processability and well tolerates natural environmental exposure.

In order to achieve the above object, the present invention mixes 1-20 phr maleic anhydride, 1-10 phr acrylic acid, and an initiator in a mixture of polyethylene and an elastomer at 110-150 ° C., and then raises the temperature to 150-200 ° C. It is a method for producing an adhesive polyethylene-elastomer blend, characterized in that the graft process.

Hereinafter, the present invention will be described in detail.

The polyethylene in the present invention is a polyolefin made of only ethylene such as low density polyethylene (LDPE), high density polyethylene (HDPE) or linear low density polyethylene (hereinafter referred to as "LLDPE"). Ethylene-α olefin copolymers may be used.

Ethylene propylene copolymer, ethylene butene-1 copolymer, etc. are used as the elastomer.

The physical properties of the selected polyethylene and elastomer have a great influence on the physical properties of the modified blend, so choose polyethylene and elastomer with physical properties that can satisfy the modified blend's properties. .

Since the blend of polyethylene and elastomer having a MI value less than 5 does not form a uniform coating even after modification, the MI value of polyethylene and elastomer should be greater than 5.

The modified adhesive polyethylene according to the present invention is an unsaturated organic acid such as acrylic acid, fumaric acid, itaconic acid, anhydride or derivative thereof, and glycidyl methacryl in the molecule of polyethylene and elastomer. It refers to a substance grafted with glucidyl methacrylate, hydroxyethyl methacrylate, and the like. Derivatives of unsaturated organic acids also include metal salts of organic acids.

In addition, modified polyethylene and elastomer blends are prepared by grafting vinylsilanes such as vinyltrimethoxysilane and methacryloyloxypro pyltrimethoxysilane onto polyethylene and elastomer molecules. can do.

Among them, maleic acid, acrylic acid, maleic anhydride, glycidyl methacrylate, and hydroxyethyl methacrylate may be used alone or in combination. Acrylic acid and maleic acid are relatively inexpensive and easily obtained. It is good to use anhydrides together.

The amount of acrylic acid and maleic anhydride varies depending on the type of polyethylene and elastomer, but acrylic acid is preferably in the range of 1-10 phr (part per hundred resin), more preferably in the range of 2-6 phr, and maleic anhydride is 1-. 20 phr range is preferred, and more preferably selected from 3-10 phr range.

Initiators include succinic acid peroxide, benzoyl peroxide, t-butylperoxy-2-ethyl hexanoate, p-chlorobenzoyl peroxide ( p-chlorobenzoyl peroxide, t-butyl peroxy isobutylate, t-butyl peroxy isopropyl carbonate, t-butyl peroxylaurate peroxy laurate), 2,5-dimethyl-2,5-di (benzoylperoxy) hexane (2,5-dimethyl-2,5-di (benzoyl peroxy) hexane), t-butyl peroxyacetate (t-butyl peroxy acetate), di-t-butyl diperoxy phthalate, t-butyl peroxy maleic acid, cyclohexanone peroxide, t-butyl T-butyl peroxy benzoate, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (2,5-dimethyl-2,5- di (t-butylperoxy) hexane), t-part T-butyl cumyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, 2,5-dimethyl-2,5- Di (t-butylperoxy) hexane-3 (2,5-dimethyl-2,5-di (t-butyl peroxy) hexane-3)), α, α-bis-t-butylperoxy-1,4 -Diisopropyl benzene ((alpha), (alpha) -bis-t-butylperoxy-1, 4-diisopropylbenzene) etc. are mentioned.

The amount of initiator used depends on the type of initiator, polyethylene and elastomer, but is preferably selected in the range of 0.01-2 phr.

The initiator, maleic anhydride, and acrylic acid are combined in the ratios described above and then the mixture is placed in a blend of already melted polyethylene and elastomer in 1-8 minutes and mixing is continued for 4-10 minutes. At this time, the rotation speed of the mixer is preferably set to 30-50rpm.

Although the temperature and time for performing the graft reaction vary depending on the type of initiator, it is generally preferable to select at least six times the half-life of the initiator.

Hereinafter, the present invention will be described in more detail with reference to the following examples.

(Example 1)

21 g LLDPE and 14 g EPR were melted in a batch type mixer rotating at 50 rpm at 130 ° C.

After melting, 2.8 g of maleic anhydride, 0.07 g of dicumyl peroxide, and 1.42 g of acrylic acid were added thereto, mixed for 5 minutes, and the temperature was raised to 180 ° C. and mixed at 180 ° C. for 1 minute.

The blend produced in the above process was sandwiched between a cold rolled steel plate with a clean surface and an aluminum thin plate having a thickness of 0.15 mm, and pressed at 180 ° C. with a hot press to form a laminate of adhesive polyethylene having a thickness of 0.15 mm.

In the laminate, gold having a width of 25 mm was formed on the aluminum thin plate portion, and then the adhesiveness of the adhesive polyethylene to aluminum was measured by a 90 ° peel test.

The peeling load (peeling load) was 10.69kg / 25mm, and the MI (Melt Flow Index) value was 5.7. Yield stress of the coating film was 26.44 MPa, the stress at break was 38.8 MPa, and the strain at break was 1017%.

(Example 2)

18 g LLDPE and 12 g EPR were put into a mixer rotating at 50 rpm at 130 ° C. for melting.

After melting, a mixture of 2.4 g of maleic anhydride, 0.06 g of dicumyl peroxide, and 1.4 g of acrylic acid was added thereto, mixed for 5 minutes, and the temperature was raised to 180 ° C., followed by mixing at 180 ° C. for 1 minute.

The blend produced by the above process was sandwiched between a cold rolled steel sheet with a clean surface and an aluminum thin plate having a thickness of 0.15 mm, and pressed at 180 ° C. with a heat press to form a laminate of adhesive polyethylene having a thickness of 0.15 mm.

In the laminate, the aluminum thin plate was cut to a width of 25 mm, and then the adhesiveness of the adhesive polyethylene to aluminum was measured by a 90 ° peel test.

The peeling load was 11.4kg / 25mm and the MI value was 5.4. The yield stress of the coating film was 27.05 MPa, the stress at break was 45.62 MPa, and the strain at break was 1064%.

(Example 3)

A blend was prepared under the same conditions as in Example 2 except that 2.4 g of maleic anhydride, 0.066 g of dicumyl peroxide, and 1.2 g of acrylic acid were added thereto, and adhesion measurement experiments were performed under the same conditions.

As a result of the measurement, the peeling load was 9.015kg / 25mm and the MI value was 5.0. The yield stress of the coating film was 31.81 MPa, the stress at break was 53.38 MPa, and the strain at break was 900.0%.

(Comparative Example)

210 g of LLDPE was added to a Brabender mixer rotating at 50 rpm at 130 ° C. for melting. Then, a mixture of 4.938 g maleic anhydride, 0.66 g of dicumyl peroxide, and 8.4 g of acrylic acid was added thereto, followed by mixing for 5 minutes, followed by temperature of 180 ° C. The mixture was raised to 180 ° C. for 1 minute and taken out.

The blend produced by the above process was placed between a cold rolled steel plate with a clean surface and an aluminum thin plate having a thickness of 0.15 mm, and pressed at 180 ° C. with a heat press to form an adhesive polyethylene head-based laminate having a thickness of 0.15 mm.

In the laminate, gold having a width of 25 mm was formed on the aluminum thin plate portion, and then the adhesiveness of the adhesive polyethylene to aluminum was measured by a 90 ° peel test.

The peeling load was 7.127kg / 25mm and the MI value was 5.1.

The blend and the EPR were mixed in proportion as shown in the following table and subjected to a 90 ° peel test under the same conditions, and the results are shown in Table 1 below.

sample LLDPE (g) EPR (g) Peeling force (kg / 25mm) EPR0-0 35 0 7.127 EPR0-30 24.5 10.5 5.844 EPR0-40 21 14 4.333 EPR0-50 17.5 17.5 3.108 EPR0-60 14 21 2.084 EPR0-70 10.5 24.5 1.412

As can be seen from the results of Table 1, 1 / (adhesive force) showed a linear function relationship proportional to the ratio of (weight of EPR / weight of PE).

The blend of the polyethylene-elastomer produced by grafting maleic anhydride and acrylic acid to the polyethylene and elastomer mixture by the method of the present invention has excellent adhesion, high mechanical strength and fluidity with a MI value of 5 or more, and coating property. It is excellent and withstands natural environment exposure and shows excellent quality.

Claims (5)

1 to 20 phr of maleic anhydride, 1 to 10 phr of acrylic acid, and an initiator were mixed in a mixture of polyethylene and an elastomer at 110-150 ° C., followed by grafting the temperature up to 150-200 ° C. Method of Making Adhesive Polyethylene-Elastomer Blend. The method of claim 1, wherein the initiator is succinic peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, p-chlorobenzoyl peroxide, t-butylperoxy isobutylate, t-butylper Oxyisopropylcarbonate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyacetate, di-t-butyldiperoxyphthalate, t-butyl Peroxymaleic acid, cyclohexanone peroxide, t-butylperoxybenzoate, dicumylperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butylcumylperoxide, t -Butylhydroperoxide, di-t-butylperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane-3, α, α-bis-t-butylperoxy-1, A process for producing an adhesive polyethylene-elastomer blend, characterized in using one selected from 4-diisopropylbenzene. 2. A process according to claim 1 wherein the amount of acrylic acid is 2-6 phr. The method of claim 1, wherein the amount of maleic anhydride is 3-10 phr. The method of claim 1 wherein the amount of initiator is 0.01-2 phr.