JPS5896525A - Polypropylene sheet for laminate and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain the titled sheet good in adhesiveness to metals and excellent in high-temperature resistance, by using a modified PP that is grafted with unsaturated carboxylic acids and is crosslinked. CONSTITUTION:A composition of a modified PP the part or whole of which is grafted with unsaturated carboxylic acids (e.g., maleic anhydride, etc.), a crosslinking additive (e.g. divinylbenzene, etc.) and a free-radical initiator (e.g. dicumyl peroxide, etc.) having a one-minute halving temperature higher than the melting point of the modified PP is molded into a sheet-like item at the melting point of the modified PP or said one-minute halving or between said temperatures, and then is heated to said one-minute halving temperature or a temperature above thereof to obtain the titled sheet. Although generally PP hardly adheres to metals, etc., when said sheet is pressed at a temperature of its melting point or above thereof onto metals or the like, a laminate can be obtained that is well bonded and excellent in high-temperature heat resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polypropylene sheet for lamination having good adhesion to metals and high temperature heat resistance, and a method for producing the same.

Since polypropylene is nonpolar, it exhibits almost no adhesion to metals. Traditionally, to improve adhesion,
■ A method of subjecting the surface of polypropylene or (and) metal to surface treatments such as corona discharge treatment, phosphoric acid treatment, flame treatment, and etching; ■ Using modified lyolefin, which is polyolein grafted with maleic anhydride. Method (for example, Japanese Patent Publication No. 42-10757, Japanese Patent Publication No. 47-4822)
, ■ A method using a composition in which acid-modified polyolein is blended with a hydrocarbon-based synthetic elastomer or an ethylene-based polymer (
For example, JP-A-52-80334, JP-A-56-21850
No.) etc. are known. However, the modified meliptetrapyrene produced by these methods.

When laminated with metal, if the temperature exceeds the melting point of the polypropylene, it easily deforms due to its own weight or external force, resulting in poor high-temperature heat resistance.In general, polymeric materials have poor melt resistance by crosslinking. It is well known that the formation is greatly improved and the high temperature resistance is improved. However,
Ho.

Lipropylene is a thermally decomposable polymer, and when it is mixed with a radical generator and heated, crosslinking does not occur, but on the contrary, it decomposes and its viscosity decreases. Therefore, in order to thermally crosslink polypropylene, a method has been adopted in which a crosslinking aid such as divinylbenzene or liquid 1.2 polybutadiene is mixed with a radical generator and heated. However, the crosslinked polypropylene obtained in this way not only does not adhere to metal at all, but it is extremely difficult to form it into, for example, a film or sheet.

As a result of extensive research into polypropylene that has good adhesion to metals and excellent high-temperature heat resistance, the present inventors have obtained a desired polypropylene sheet for lamination by crosslinking modified polypropylene, thereby providing the present invention. That's exactly what happened. That is, according to the present invention, there is provided a polypropylene sheet for lamination made of modified polypropylene which is partially or entirely grafted with unsaturated carbon #s and whose main chain is crosslinked. Although there are no particular restrictions on the method for producing the propylene sheet for lamination of the present invention, the following method is particularly recommended. That is, a composition consisting of a modified polypropylene partially or entirely grafted with unsaturated carboxylic acids, a crosslinking auxiliary agent, and a radical generator having a 1-minute half-life temperature higher than the melting point of the modified polypropylene is prepared at a temperature higher than the melting point of the modified polypropylene. production of a polypropylene sheet for lamination, which is characterized in that it is formed into a sheet at a temperature lower than the 1-minute half-life temperature of the radical generator, and then heated to a temperature higher than the 1-minute half-life temperature of the radical generator. A method is provided. In addition, a composition consisting of melipropylene, an unsaturated carboxylic acid, a cross-linking agent, and a radical generator having a half-life temperature of -1 minute higher than the melting point of the polypropylene is added to This polypropylene sheet for lamination is characterized in that it is formed into a sheet at a temperature lower than the one-minute half-life temperature, and then heated to a temperature higher than the one-minute half-life temperature of the radical generator.

The modified polypropylene used in the present invention is obtained by grafting unsaturated carbon 111fii onto polypropylene by any method. The content of unsaturated carboxylates in the modified polypropylene is generally preferably from o, oos to 5,000 yen by weight. The method for producing such modified polypropylene is not particularly limited, and for example, a method of reacting it in a molten state (for example, Japanese Patent Publication No. 43-27
421), a method of reacting in a solution state (for example, Japanese Patent Publication No. 44-15422), a method of reacting in a slurry state (for example, Japanese Patent Publication No. 43-18144), a method of reacting in a vapor phase (for example, Japanese Patent Application Publication No. 1973-1983). -'77493).

The polypropylene used in the present invention is not particularly limited, and examples include homopolypropylene, propylene-ethylene block copolymers, propylene-ethylene random copolymers, copolymers of propylene and α-olefin, and mixtures thereof. used. Among these, propylene-ethylene random copolymers and propylene-ethylene vinyl copolymers are particularly preferably used. The la of these polypropylenes varies depending on the tacticity and comonomer content, but is generally in the range of 130 to 170°C.

Examples of unsaturated carbon #s used in the present invention include acrylic alcohol, methacrylic fi! , maleic acid, 7 malic acid, itacon I! ! , Citracon #.

Also, these acid anhydrides, esters, electrodes, imides, gold j
IK salts, etc., such as maleic anhydride.

Anhydrous citracone, anhydrous itacone layer, acrylic sapon methyl, strict ethyl methacrylate, butyl acrylate, butyl methacrylate, glycidyl acrylate, glycidyl methacrylate, maleic acid monoethyl ester, maleic acid diethyl ester, heptamalic acid monomethyl ester, fumaric acid Acid dimethyl ester, itaconic acid monomethyl ester, itaconic acid diethyl ester, acrylamide, methacrylamide, maleic acid monoacrylamide, maleic acid diamide, maleic acid-N-monoethylamide, maleic acid-
M, M-diethylamide, maleic acid-Natsuichi monobutylamide.

Maleic acid-M, M-dibutylamide, Amarken monoamide, fumaric acid diamide, fumaric acid-N-monoethylamide, fumaric acid-M, M-diethylamide, fumaric acid-
Violet-motuptilamide.

Fumar 9%-N,N-dibutylamide, maleimide.

N-butyl maleide, M'-7. Examples include nilmalicede, sodium acrylate, sodium methacrylate, potassium acrylate, and potassium methacrylate. Among these, it is most preferable to use maleic anhydride.

The crosslinking auxiliary agent used in the production method specified by the present invention is a compound having two or more double bonds in the molecule, and includes, for example, divinylbenzene, diallyl phthalate, triallyl glycerate, and diene monomer as main components. A liquid rubber having a number average molecular weight of 500 to 10,000, for example, 1.2-polybutadiene, 1.4-polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, or a carboxyl group, hydroxyl group, Mercapto group, halogen atom, amino group,
1, 2 with functional groups such as aziridino groups and epoxy groups
-Polybutadiene, 1,4-polybutadiene, polyisoprene.

Polychloroprene, 1,2-polypentadiene.

Styrene-butadiene copolymer, acrylonitrile-
Examples include butadiene copolymers, butadiene-isoprene copolymers-butadiene-pentadiene copolymers, and divinylbenzene and liquid 1,2-polybutadiene are preferably used. The amount of the crosslinking aid added is 1 to 50 parts by weight per 100 parts by weight of modified polypropylene or polypropylene, preferably 3 to 30 parts by weight per 100 parts by weight of modified polypropylene or polypropylene. If the amount of the crosslinking auxiliary agent added is less than 1 part by weight, the rigidity, which is effective in improving high temperature heat resistance, will be significantly lowered, which is undesirable.

The method for crosslinking modified ribrivirene in the present invention is not necessarily limited to a method using a crosslinking agent. For example, modified polypropylene. The degree of such crosslinking is 10 to 90 degrees, preferably 30 to 80 degrees as a gel fraction. That is, if the degree of crosslinking is too high, adhesion will be poor in the case of the seed layer, so it is preferable. The temperature (10 degrees Celsius) is higher than the melting point of the modified polypropylene or polypropylene (the peak temperature of the endothermic curve measured with a differential scanning calorimetry needle at a heating rate of 10 degrees Celsius/minute), preferably 10 degrees Celsius or more higher. Since the melting point of modified polypropylene or polypropylene is in the temperature range of 130 to 170°C,
A radical generator having a 1-minute half-life temperature of 130° C. or higher, preferably 140° C. or higher can be used. Examples of radical generators used in the present invention include 2,4.4-trimethylpentyl-2-hydroperoxide, diisopropylbenzene octadrovar oxide, cumene octadrovar oxide, and t-butyl octadrovar oxide. oxide, dicumyl peroxide 2.5, trimethyl-2,'5'-di(1=-butylperoxy)-hexane, 1,3-bis-(t-butylperoxy-isopropyl)-benzene, t -butyl methyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di&-(t-butylperoxy)-hexyne-3,1,1-di-(1liptylperoxide) luperoxy-3,3,5-)limethylcyclohexane, 1.1-di-t-butylperoxycyclohexane, 2.2-L-di(t-butylperoxy)-butane, 4.4-di-t- Butyl baroxyvaleric acid n-butyl ester.

Di-t-butylperoxy-hexahide p-tereathalate, di-t-butylperoxyazelate, t-butylperoxy-3,5,5-trimethylhexolate,
t-Butylperoxyacetate, t-butylperoxybenzoate.

t-Butyl baroxyisopropyl carbonate, succinic acid peroxide, vinyl tris-(1
-butylperoxy)silane, etc. The amount of the radical generator to be added varies depending on the amount of the crosslinking aid, but is generally preferably 0.1 to 10 parts by weight per 100 parts of modified polypropylene or propylene. If the amount of the radical generator added is less than 0.1 part by weight, the degree of crosslinking will be low, and if it exceeds 10 parts by weight, it will decompose and the effect of improving high temperature heat resistance will be small (12), which is not preferable.

In the production method of the present invention, modified polypropylene, a crosslinking aid, a radical generator, and in some cases other unmodified polypropylene, other polymeric substances other than polypropylene, inorganic or organic fillers, and heat-resistant stabilizers are used. , weatherproofing agent, lubricant,
Additives such as nucleating agents, m-materials, dyes, m-fuels, and anti-blocking agents are mixed. In another embodiment, polypropylene, unsaturated carboxylic acids, crosslinking aids, radical generators, and optionally other polymeric substances other than pyrene and fillers.

Mix other additives. Mixing is carried out using a tumbler blender, a v-type blender, a hexagonal mixer, a lumixer, a ribbon mixer, or the like.

In some cases, a mixture of these may also be used.

- It is also possible to melt-knead the modified polypropylene or polypropylene at a temperature higher than the melting point of the polypropylene and lower than the one-minute half-life temperature of the radical generator using an extruder, a mixing machine, a Banbury hawk mixer, or the like.

Next, the composition thus obtained is formed into a film or sheet (hereinafter collectively referred to as a sheet) at a temperature lower than the one-minute half-life temperature of the radical generator (13). The coloring method is not particularly limited, for example! This can be carried out using an extruder with a die, a calendar molding machine, a compression molding machine, etc.Next, the sheet-like material obtained in the above manner is heated to a temperature higher than the 1-minute half-life temperature of the radical generator. Heat. The heating method is not particularly limited, and examples include air bath heating, liquid bath heating, and 1wA body contact heating.

Examples include infrared heating and high frequency heating. The heating time varies depending on the decomposition temperature of the radical generator, but is generally 1
0 seconds to 1 hour is appropriate.

By pressing the thus obtained polypropylene sheet of the present invention with a metal or the like at a temperature higher than the melting point of the sheet, a laminate having good adhesion and excellent high temperature heat resistance can be obtained. There are no particular restrictions on the metals used for lamination, including iron, aluminum, aluminum, nitrogen, gold, silver, copper, magnesium, zinc, tin, lead, steel, stainless steel, and metal (14
), tinplate, etc., with iron and aluminum being preferably used.

The polypropylene/metal laminate obtained in the above manner has strong adhesive strength between the two, excellent high-temperature heat resistance, and has both the excellent characteristics of polypropylene and the excellent characteristics of metal. It also has excellent new features that are not available in other countries, so it can be effectively used as automobile materials, industrial materials, building materials, beverage cans, packaging materials for various foods, etc.

Examples of the laminate of the present invention are shown below, but the present invention is not limited to these.

The adhesive strength and high temperature heat resistance of the laminates in Examples were measured by the following methods.

The adhesive strength is 0 between two 2CI+1m gold sheets.
．． It is expressed as T-peel strength of a three-layer laminate having a layer of modified polypropylene composition 1 ff thick. Measurements were made at 23°C.
It was carried out at 50% RH and at a pulling speed of 20 m+11/min.

The measurement of high temperature heat resistance will be an overlap length of 2CI+ (15
) 0, 11 between two parallel metal sheets facing each other
A layered waste product having a polypyrene composition layer with a thickness of 11 was placed in an open chamber at 200°C, one metal sheet was suspended with a wire, and a load of 20 of was applied to the lower metal sheet in the bale for 10 minutes. It is expressed as the time until the metal sheet separates. The thickness of the metal sheet was 0.2 m for the iron sheet and 0.141 m for the aluminum sheet, and these were sufficiently degreased.

Example! M1 knee 0.6#/10 minutes, 100 parts by weight of propylene-ethylene random copolymer with ethylene content of 2.0 weight arc, 112 parts by weight of maleic anhydride, 2.5-dimethyl-2,
0.12 parts by weight of 5-di(t-butylperoxy)-hexane, 1 part by weight of butylated hydroxytoluene O, 11 parts by weight of stearic calcium O, were mixed for 5 minutes in a Henschel mixer, and L/D = 24. Melt-kneading pelletization was performed at 220° C. using a 4oval extruder, and then heat treatment was performed at 145° C. for 4 hours using a constant humidity dryer to obtain a modified polypropylene (16). This modified polypropylene contained a graft of 0.5 molar maleic anhydride.

This modified l dipropylene 15-layer lid, MIF knee 4. (
1710 minutes, unmodified propylene-ethylene random copolymer with ethylene content 3.0% by weight (iM point 140°C) 8
A composition consisting of 5 parts by weight, 10 parts by weight of divinylbenzene, 2.0 parts of dicumyl peroxide (halved in 1 minute at 1179°C), 11 parts of butylated droxytol 1201 parts by weight, and 0.1 parts of calcium stearate was prepared by Henschel. Mix with a mixer for 5 minutes! -1 by extruder with die
The Sea F obtained by making noodle balls from a sheet with a thickness of 01lff at 65°C was sandwiched between two aluminum sheets with a width of m, and heated at a temperature of 240°C and a pressure of io'9/C- for 5 minutes. It was pressed and heated. The obtained laminate had an I11 strength of 2.319/2C/ml and a high temperature heat resistance of 1 hour or more.

(17) Comparative Example 1 The same procedure as in Example 1 was carried out except that benzoyl peroxide (1 minute half-life temperature: 130° C.) was used instead of dicumyl peroxide. When extruding into a sheet, the extrudate became flaky and no sheet could be obtained.

Comparative Example 2 The same procedure as in Example 1 was carried out except that the sheet extrusion temperature was changed to 220°C. The extrudate became flaky and no sheet was obtained.

Comparative Example 3 The same procedure as in Example 1 was carried out except that the modified polypropylene was not added and the amount of the unenviable propylene-ethylene silane random copolymer was 100 parts by weight. The resulting laminate! The lI adhesion strength was 0.

Comparative Example 4 The same procedure as in Example 1 was repeated except that dicumyl peroxide (18) was not added. The adhesive strength of the obtained laminate was (16'9/2"@high temperature heat resistance was 70 seconds).

Comparative Example 5 The same procedure as in Example 1 was carried out except that divinylbenzene and dicumyl peroxide were not added. The adhesive strength of the obtained laminate was 1.919/2C
1+, high temperature heat resistance was 80 seconds.

Example 2 15 parts by weight of modified polypyrene obtained in Example 1,
85 parts by weight of unmodified propylene-ethylene block copolymer (melting point 160°C) with MF knee 1.5N/10 minutes and ethylene content 2.7% by weight.

40 parts by weight of calcium carbonate with an average particle size of 1.2μ.

Liquid modified 1.2-polybutadiene 2 with number average molecular weight 1000
0 parts by weight, 2.5-dimethyl-2,5-di(1-butylperoxy)-hexyne-3 (1 minute half-life temperature 193
℃) Triple lid, 01 parts by weight of butylated hydroxytoluene, and 0.1 parts by weight of stearic acid (19) lucium.

Mixed for 5 minutes in a lumixer, 17 minutes in an OOM extruder
Melt mixed wire pelletization was carried out at 0°C.

From the obtained modified polypropylene composition pellets! - 2 sheets of 0.1 a thick at 175℃ using an extruder with a die.
Sandwiched between cm1 wide iron sheets, temperature 240℃, 1
Pressing was carried out for 10 minutes at a pressure of 01q/cd. The adhesive strength of the laminate thus obtained is 12.7~/2 el
l, high temperature heat resistance was 1 hour or more.

Comparative Example 6 In Example 2, 2,5-dimethyl-2,5-di(
The same procedure as in Example 2 was carried out except that benzoyl peroxide was used instead of 1-butylperoxy)-hexyne-3. During pelletization using an OOM extruder, the extrudate became flaky and good pellets could not be obtained.

(20) Comparative Example 7 The same procedure as in Example 2 was carried out except that the modified polypropylene in Example 2 was not added and the unmodified propylene-ethylene brick copolymer was used in an amount of 1001 parts by weight. The adhesive strength of the resulting laminate was zero.

Comparative Example 8 In Example 2, 2,5-dimethyl-2,5-di(t
The same procedure as in Example 2 was carried out except that r-butylperoxy)-hexyne-3 was not added. The adhesive strength of the obtained laminate was 0.5'! /2CIIl+ high temperature heat resistance was 60 seconds.

Comparative Example 9 In Example 2, liquid 1,2-polybutadiene and 2
．． The same procedure as in Example 2 was carried out except that 5-dimethyl-2,5-di(t-butylperoxy)-hexyne-3 was not added. The adhesive strength of the obtained laminate was 10.21
cp/2C+a, high temperature heat resistance was 110 seconds.

(21) Example 3 myx-0.6f, 410 minutes, propylene-ethylene random copolymer with ethylene content of 30% (melting point 140°C)
100 parts by weight, 5 parts by weight of calcium methacrylate, 10 parts by weight of divinylbenzene, dicumyl peroxide (
1 minute cow humidity reduction 179°C) 2.0 parts by weight, butylated hydroxytoluene 01 parts by weight, calcium stearate 0
, 1 part by weight were mixed for 5 minutes in a Henshi mixer, and T-
Use an extruder with a die! 2CI thickness 01-) at 1165℃
The material was pressed between two aluminum sheets of one width at a temperature of 220°C and a pressure of 1aJ9/c- for 5 minutes. The adhesive strength of the laminate thus obtained was 4.5&p, /'20
m, high temperature heat resistance was 1 hour or more.

Comparative Example 10 Example 3 was carried out in the same manner as in Example 3, except that benzoyl peroxide (1 minute and a half (22), reduced temperature 130° C.) was used instead of dicumyl peroxide F. In the case of sheet molding, the extrudate became flaky and no sheet could be obtained.

Comparative Example 11 The same procedure as in Example 3 was carried out except that the sheet extrusion temperature was changed to 220°C.

The extrudate became flaky and no sheet was obtained.Comparative Example 12 The same procedure as in Example 3 was carried out except that calcium methacrylate was not added.

The adhesive strength of the obtained laminate was 0.

Comparative Example 13 The same procedure as in Example 3 was conducted except that divinylbenzene was not added in ψ and the dicumyl peroxide addition lid was changed to 0.1 parts by weight. The adhesive strength of the obtained laminate is 1
．． 5 kg/2 C'1 m high temperature heat resistance was 10 seconds or less.

Comparative example 14 In Example 3, dicumyl peroxide (23) The same procedure as in Example 3 was carried out except that .

The adhesive strength of the obtained laminate was 0.2jI9/2c11.
High temperature heat resistance was 60 seconds.

Example 4 Propylene-ethylene block copolymer with MW eny, 5F/10 min, ethylene content 27ml1% (melting point 160°C
) 100 parts by weight, calcium carbonate 40 with an average particle size of 12μ
Parts by weight, anhydrous maleic MO 95 parts by weight, number average molecular weight 1
2.000 liquid 1.2-polybutadiene 20 parts by weight;
5-dimethyl-2,5-di(t-butylperoxy)
- Hexyne-3 (1 minute half-life temperature: 193°C) 3 parts by weight.

0.1 part by weight of butylated hydroxytoluene and 0.1 part by weight of calcium stearate were mixed in a Henschel mixer for 5 minutes, and the mixture was melt-kneaded and pelletized using a 00M extruder at 170°C. From the obtained polypropylene composition pellets! -Thickness 0.1ff at 175℃ using extruder with die
A sheet was formed. Subsequently, the obtained sheet was heated at 250° C. for 20 minutes using an infrared heater.

(24) Place this sheet between 2cm+m wide iron sheets.
Pressure bonding was carried out for 10 minutes at a humidity of .degree. C. and a pressure of 10'9/cd.

The adhesive strength of the laminate thus obtained was 8.3'
9/2 L3, high temperature heat resistance was 1 hour or more.

Comparative Example 15 In Example 4, 2,5-dimethyl-2,5-di(
The procedure of Example 4 was repeated except that benzoyl peroxide was used in place of 1-butylperoxy)-hexyne-3. During pelletization using the OOM extruder, the extrudate became flaky and clean pellets could not be obtained.

Comparative Example 16 The same procedure as in Example 4 was carried out except that the sheet extrusion humidity was changed to 220°C. The extrudate had a 7-lake shape and no sheet was obtained.

Comparative Example 17 The same procedure as in Example 4 was carried out except that maleic anhydride was not added.

(25) The adhesive strength of the obtained laminate was 0.

Comparative Example 18 In Example 4, liquid 1.2-*: Liptadiene was not added and the amount of 2,5-dimethyl-2,5-di(t-butylperoxy)-hexyne-3 was 0.1 parts by weight. The same procedure as in Example 2 was carried out except for the following. The adhesive strength of the obtained laminate was 6.019/2C+m, and the high temperature heat resistance was 10 seconds or less.

Comparative Example 19 In Example 4, 2,5-dimethyl-2,5-di(
The same procedure as in Example 4 was carried out except that 1-butylperoxy χ-hexyne-3 was not added. The adhesive strength of the obtained laminate is 0.1 & 9/201 m, and the high temperature heat resistance is 290
It was seconds.

patent applicant Tokuyama Soda Co., Ltd. (26)

Claims (1)

[Claims] (1) A laminated polypropylene sheet made of modified polypropylene that is partially or entirely grafted with unsaturated carboxylic acids and crosslinked. (2) A polypropylene sheet for lamination made of modified polypropylene that is partially or entirely grafted with unsaturated carboxylic acids. modified polypropylene,
Crosslinking aid. and a radical generator having a one minute half humidity higher than the melting point of the modified polypropylene, which is formed into a sheet at a temperature higher than the melting point of the modified polypropylene and lower than the one minute half humidity of the radical generator; (3) A method for manufacturing a polypropylene sheet for lamination, characterized in that the radical generating agent is heated to a temperature equal to or higher than the 1-minute half-life temperature of the radical generating agent. Manufacturing method (4)
The crosslinking aid is divinylbenzene or liquid l. 2-polybutadiene The manufacturing method (5) according to claim 5, wherein the radical generator is dicumyl peroxide or 2,5-dimethyl-2,5-di(t-butylperoxy)-hexyne- (6) A composition comprising propylene, an unsaturated carboxylic acid, a crosslinking aid, and a radical generator having a half-life temperature of -1 minute higher than the melting point of the polypropylene. , a lamination characterized in that the polypropylene is formed into a sheet at a temperature above the melting point of the polypropylene and below the 1-minute half-life temperature of the radical generator, and then heated to a temperature above the 1-minute half-life temperature of the radical generator. (7) The unsaturated carboxylic acid WR is maleic anhydride, and (8) the crosslinking aid is divinylbenzene or liquid 1.2-
The manufacturing method (9) according to claim (6), wherein the radical generator is polybutadiene, wherein the radical generator is dicumyl peroxide or 2,5-dimethyl-2,5-di(t-butylperoxy)-hexyne-3 Claim No. (6)
The method of making rice cake described in the section