JPH0971696A - Highly transparent polypropylene sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a highly transparent polypropylene sheet having properties of markedly improved transparency and moldability and excellent in stiffness, heat resistance, chemical resistance by compounding specific three kinds of chemicals to crystalline polypropylene and forming a sheet. SOLUTION: This sheet is produced by forming the composition composed of (A) 100 pts.wt. of crystalline polypropylene, (B) 0.01-5 pts. of a compound selected from the group consisting of an alkali metal carboxylate, an alkali metal β-ketonate and a β-ketoacetic ester alkali metal salt (preferably a Li 8-20C aliphatic monocarboxylate), (C) 0.01-5 pts. of a cyclic organic phosphoric ester basic polyvalent metal salt of formula I [R1 is H, a 1-4C alkyl; R2 and R3 are each H, a 1-12C alkyl; M is a metal atom of III and IV group in the periodic table; X is HO- when M is a III group metal, X is O= or (HO)2 - when M is a IV group metal] and (D) 0.02-0.1 pt. of a lithium aluminum double hydroxide salt compound of formula II (X is an anion; n is valence number of X; M<=3).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a highly transparent polypropylene sheet having excellent moldability.

[0002]

2. Description of the Related Art Polypropylene resins are widely used in the fields of food containers, medical instruments, physicochemical equipment, etc. because they can be used to obtain film molded products and sheet molded products with excellent heat resistance, chemical resistance and rigidity. However, the transparency was insufficient. As a method of improving transparency, a method of adding a metal salt of carboxylic acid, a metal salt of aromatic sulfonic acid, a metal salt of aromatic acid phosphoric acid, a sorbitol compound, etc. as a nucleating agent (for example, JP-A-58). No. 25341 and Japanese Patent Laid-Open No. 56-30449) have been proposed. Of these methods, the addition of a sorbitol-based compound is most effective for improving transparency, but it has problems such as poor heat resistance and rigidity, odor generation, and bleed-out. Since the nucleating agent volatilizes, problems such as deterioration of the work environment due to odor and deterioration of the surface quality of the sheet molded product due to contamination of the roll may occur, so it is conceivable to lower the cooling temperature of the roll. The temperature could not be lowered sufficiently. Further, the formed sheet also produces a residual odor, so that its use is limited.

Further, as a method other than the addition of the nucleating agent, there are a quench solidification method and a stretching method at the time of forming a sheet, but since the transparency is lost by heating, the sheet cannot be used for thermoforming and is rapidly solidified. The law alone does not provide sufficient transparency. On the other hand, in the stretching method, the transparency is insufficient, and by heating,
The sheet could not be used for thermoforming due to shrinkage and loss of transparency.

As described above, none of the conventional methods satisfies both high transparency and good moldability.

[0005]

DISCLOSURE OF THE INVENTION The present invention has remarkably improved transparency and moldability, and further has excellent characteristics such as rigidity, heat resistance, chemical resistance, low elution and odorlessness, and is a food container, An object of the present invention is to provide a highly transparent propylene sheet suitable for medical containers, physics and chemistry equipment and the like.

[0006]

Means for Solving the Problems As a result of studying the above-mentioned problems, the present inventors have found that a highly crystalline polypropylene resin has a specific alkali metal compound, a specific cyclic organic phosphate ester basic polyvalent metal salt, and a specific polyvalent metal salt. Using a composition containing the lithium aluminum complex hydroxide salt compound of
The inventors have found that a highly transparent polypropylene sheet can be obtained by lowering the roll cooling temperature during sheet forming, and completed the present invention.

That is, the highly transparent polypropylene sheet of the present invention comprises (a) 100 parts by weight of a crystalline polypropylene resin, and (b) an alkali metal carboxylate, an alkali metal β-diketonate and an alkali metal β-keto acetic acid ester salt. At least one selected from the group consisting of 0.
01 to 5 parts by weight, and (c) the following general formula (I) of [Chemical Formula 3] (the same as [Chemical Formula 1]):

[0008]

Embedded image (In the formula, R ₁ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ and R ₃ represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and M represents
A metal atom of group III or group IV of the periodic table is shown,
X represents HO- when M represents a metal atom of Group III of the periodic table, and O = or (HO) ₂ -when M represents a metal atom of Group IV of the periodic table. Show. 0.01 to 5 parts by weight of at least one cyclic polyphosphoric acid ester basic polyvalent metal salt represented by the formula (4), and (d)
General formula (II) of (same as [Chemical Formula 2]):

[0009]

[Al ₂ Li (OH) ₆ ] _n X.mH ₂ O (II) (wherein, X is an inorganic or organic anion, n is the valence of the anion (X), and m is 3 or less. A lithium aluminum complex hydroxide salt compound represented by
It is characterized in that it is blended with 0.02 to 0.1 part by weight to form a sheet.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION (a) The crystalline polypropylene resin of the present invention is a homopolymer of propylene, or a random or block copolymerization of propylene with an α-olefin such as ethylene, butene-1, or hexene-1. It is a coalesced product and polypropylene constitutes the crystal part, and melt flow rate (MFR) (JIS K721
0; load 2.16 kg, 230 ° C.) 0.3 to 10 g / 1
It is preferably 0 min. Among these, a propylene homopolymer and a propylene-ethylene random copolymer are preferable, and for example, in the propylene-ethylene random copolymer, one having an ethylene content of 2 to 5% by weight is preferably used.

This crystalline polypropylene resin is usually
Transition metal compound catalyst components such as titanium trichloride and titanium tetrachloride, or catalyst components obtained by supporting them on a carrier whose main component is magnesium halide such as magnesium chloride, and organoaluminum such as triethylaluminum and diethylaluminum chloride. It is prepared using a catalyst in combination with a compound.

Further, as the alkali metal constituting the alkali metal carboxylate, the alkali metal β-diketonate or the alkali metal β-ketoacetic acid ester salt of the component (b) of the present invention, lithium is lithium, Examples include sodium and potassium.

Examples of the carboxylic acid which constitutes the alkali metal carboxylate include acetic acid, propionic acid, acrylic acid, octylic acid, isooctylic acid, nonanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, Stearic acid, oleic acid, ricinoleic acid, 12-
Fats such as hydroxystearic acid, behenic acid, montanic acid, melissic acid, β-dodecylmercaptoacetic acid, β-dodecylmercaptopropionic acid, β-N-laurylaminopropionic acid, β-N-methyl-N-lauroylaminopropionic acid Group monocarboxylic acids; malonic acid, succinic acid, adipic acid, maleic acid, azelaic acid, sebacic acid, dodecanedioic acid, citric acid, butanetricarboxylic acid,
Aliphatic polycarboxylic acid such as butanetetracarboxylic acid;
Naphthenic acid, cyclopentanecarboxylic acid, 1-methylcyclopentanecarboxylic acid, 2-methylcyclopentanecarboxylic acid, cyclopentenecarboxylic acid, cyclohexanecarboxylic acid, 1-methylcyclohexanecarboxylic acid, 4
-Methylcyclohexanecarboxylic acid, 3,5-dimethylcyclohexanecarboxylic acid, 4-butylcyclohexanecarboxylic acid, 4-octylcyclohexanecarboxylic acid,
Cyclohexenecarboxylic acid, 4-cyclohexene-1,
Alicyclic mono- or polycarboxylic acids such as 2-dicarboxylic acid; benzoic acid, toluic acid, xylyl acid, ethylbenzoic acid, 4-tert-butylbenzoic acid, salicylic acid, phthalic acid,
Examples thereof include aromatic mono- or polycarboxylic acids such as trimellitic acid and pyromellitic acid.

Examples of the β-diketone compound constituting the alkali metal β-diketonate include acetylacetone, pivaloylacetone, palmitoylacetone, benzoylacetone, pivaloylbenzoylacetone, dibenzoylmethane and the like.

Examples of the β-ketoacetic acid ester constituting the alkali metal β-ketoacetic acid ester salt include, for example, ethyl acetoacetate, octyl acetoacetate, lauryl acetoacetate, stearyl acetoacetate, ethyl benzoylacetate, lauryl benzoylacetate. And so on.

Further, the alkali metal carboxylate, alkali metal β-diketonate or alkali metal β-ketoacetic acid ester salt which is the component (b) is the above-mentioned alkali metal and carboxylic acid, β-diketone compound or β-dye, respectively.
It is a salt with ketoacetate and can be produced by a conventionally known method. Further, among the respective alkali metal salt compounds of the component (b), an alkali metal aliphatic monocarboxylic acid salt, particularly a lithium aliphatic carboxylic acid salt is preferable, and particularly, an aliphatic monocarboxylic acid having 8 to 20 carbon atoms. Acid salts are preferred.

The number of carbon atoms represented by R ¹ in the cyclic organic phosphoric acid ester basic polyvalent metal salt represented by the general formula (I) of the above [Chemical formula 1] which is the component (c) of the present invention. Examples of the alkyl group of 1 to 4 include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl and the like, which has 1 carbon atom represented by R ² or R ^3.
Examples of the alkyl group of ~ 12 include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl,
Amyl, tertiary amyl, hexyl, heptyl, octyl,
Isooctyl, tertiary octyl, 2-ethylhexyl, nonyl, isononyl, decyl, isodecyl, undecyl,
Examples include dodecyl and third dodecyl.

Examples of the metal atom of group III or group IV of the periodic table represented by M include aluminum, gallium, germanium, tin, titanium and zirconium, and aluminum is particularly preferable.

Therefore, as the cyclic organic phosphoric acid ester basic polyvalent metal salt represented by the general formula (I) of the above [Chemical formula 1], for example, compounds shown in the following [Chemical formula 5] to [Chemical formula 10] (1) to (6) and the like.

[0020]

Embedded image

[0021]

[Chemical 6]

[0022]

[Chemical 7]

[0023]

Embedded image

[0024]

Embedded image

[0025]

Embedded image

The above-mentioned cyclic organic phosphoric acid ester basic polyvalent metal salt is obtained, for example, by reacting an alkali metal salt of an acidic cyclic organic phosphoric acid ester with a polyvalent metal halide or an oxidized polyvalent metal halide, and thereafter, if necessary. It can be easily produced by a method of hydrolysis, a method of reacting an acidic cyclic organic phosphoric acid ester with a polyvalent metal alkoxide, and then hydrolyzing as necessary.

Incidentally, as a concrete example of the production of the cyclic organic phosphate ester basic polyvalent metal salt, there is disclosed in JP-A-5-15.
It is disclosed in Japanese Patent No. 6078.

Further, the lithium aluminum composite hydroxide salt compound which is the component (d) of the present invention is a compound represented by the general formula (II) of the above [Chemical Formula 2].

Specifically, the following lithium aluminum complex hydroxide salt compounds can also be used. That is, as the inorganic or organic anion for X in the general formula, carbonic acid, sulfuric acid, chlorine oxyacid (for example, perchloric acid), phosphorus oxyacid (phosphoric acid, phosphorous acid, metaphosphoric acid), etc. are obtained. One or a combination of two or more of the above-mentioned anions is preferable, but acetic acid, propionic acid, adipic acid, benzoic acid, phthalic acid, terephthalic acid, maleic acid,
Anions obtained from fumaric acid, succinic acid, p-oxybenzoic acid, salicylic acid, picric acid and the like can be mentioned.

The highly transparent polypropylene sheet of the present invention contains, in addition to the above-mentioned respective components, an antioxidant, an inorganic filler, an electrification agent and an electrification agent which are usually used for a crystalline propylene resin within a range not impairing the object of the present invention. Other additives such as an inhibitor, an ultraviolet absorber, a light stabilizer, an antiblocking agent, a lubricant, a pigment and a dye can be added.

The amount of each of the above components is 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, of the alkali metal compound as the component (b), relative to 100 parts by weight of the crystalline polypropylene resin (a). It is a department. When the amount of the component (b) is less than 0.01, heat resistance, rigidity and transparency are lowered, while when it exceeds 5 parts by weight, the effect of the present invention is not exhibited. Also,
The amount of the cyclic organic phosphate ester basic polyvalent metal salt as the component (c) is 0.01 to 5 parts by weight, preferably 0.03 to 3 parts by weight. When the amount of the component (c) is less than 0.01, heat resistance, rigidity and transparency are lowered, while when it exceeds 5 parts by weight, the effect of the present invention is not exhibited. Furthermore, the blending amount of the lithium aluminum composite hydroxide salt compound of the component (d) is 0.0
The amount is 2 to 0.1 parts by weight, and if the amount is less than 0.02 parts by weight, the rigidity and transparency are lowered, and if the amount is more than 0.1 parts by weight, the effect of the present invention is not exhibited.

The highly transparent polypropylene sheet of the present invention is prepared by kneading the above components using a Henschel mixer, a super mixer, a ribbon blender, etc., and then a conventional single-screw kneader, a twin-screw kneader, a Banbury mixer, a ribbon blender, etc. It can be obtained by melt-kneading at 170 to 300 ° C. with a conventional sheet forming method such as a three-stage roll type, touch roll type, air knife type, etc., but in order to improve transparency, melt kneading Temperature is 240 ~
The temperature at 260 ° C. and the roll cooling temperature at the time of sheet molding is preferably 70 ° C. or lower, and more preferably 20 to 50 ° C.

[0033]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these descriptions.

The following resin raw materials and additives were used in each of the examples and comparative examples. (A) Crystalline polypropylene resin (PP) Propylene-ethylene random copolymer: Melt flow rate (MFR) (230 ° C, 2016 kg load)
0 g / 10 minutes, ethylene content 3% by weight (bc) Component: Mixture of alkali metal salt and cyclic organic phosphate ester basic polyvalent metal salt "NA-21" (manufactured by Asahi Denka Co., Ltd.) (d) Ingredients: Mizukalak (Mizusazawa Chemical Co., Ltd.) (e) Ingredients: Gelall MD (New Japan Rika Co., Ltd.)
[1,3,2,4-di (p-methylbenzylidene) sorbitol] (f) Antioxidant: 2,6-t-butyl-p-cresol (BHT) Further, the physical properties of the test pieces of each example were measured. The procedure was as follows. (1) Haze value (%): ASTM D 1003-61
Compliance (2) Odor: Existence of odor was checked (yes ... ×,
None ・ ・ ・ ○) (3) Processing formability: When a roll having a mirror surface is washed with a solvent and used for sheet formation, a glossy sheet has a dull portion due to stains on the roll surface. Continuous molding time of 12 hours or more .... ◎ More than 8 hours and less than 12 hours ... ○ More than 3 hours and less than 8 hours・ ・ ・ ・ × Less than 3 hours ・ ・ ・ ・ ・ ・ ・ ・ ××

Example 1 With respect to 100 parts by weight of crystalline polypropylene resin, (b
After mixing 0.10 parts by weight of the component c) and 0.05 parts by weight of the component (d) and further adding 0.1 parts by weight of an antioxidant and dry blending with a Henschel mixer, a single screw extruder (50 mm, L / D = 28) and die outlet temperature 240 ° C
Extruding roll is cooled to a temperature of 50 ° C. to form a sheet (thickness: 800 μm) using a sheet forming machine whose roll surface is a mirror surface and is a three-stage roll type, and this sheet is used as a test piece.
Physical properties such as haze value and odor were measured. Table of measurement results
It is shown in FIG.

Examples 2 to 4 Sheets were molded in the same manner as in Example 1 except that the component (bc) was added in the proportions shown in Table 1, and the physical properties were measured. The measurement results are shown in Table-1.

Comparative Example 1 A sheet was formed by the same method as in Example 1 except that 0.005 parts by weight of the component (bc) was added, and the physical properties were measured. The measurement results are shown in Table-1.

Comparative Example 2 A sheet was formed in the same manner as in Example 1 except that the component (e) was added in an amount of 0.25 part by weight, and its physical properties were measured.
The measurement results are shown in Table-1.

Comparative Example 3 0.002 parts by weight of component (d) and 0.1 parts of component (bc)
A sheet was formed by the same method as in Example 1 except that 0 part by weight was added, and the physical properties were measured. The measurement results are shown in Table-1.

Example 5 With respect to the same composition as in Example 3, the sheet was formed by changing the roll cooling temperature (30 ° C., 50 ° C., 70 ° C.) at the time of sheet forming, and the physical properties were measured. Table 2 shows the measurement results.

Comparative Example 4 With respect to the same composition as in Comparative Example 2, the sheet was formed by changing the roll cooling temperature (30 ° C., 50 ° C., 70 ° C.) at the time of sheet forming, and the physical properties were measured. Table 2 shows the measurement results.

Example 6 With respect to the same composition as in Example 3, a combination of a mat roll and an air knife type was used as a sheet forming method, and a roll cooling temperature (20 ° C., 4 ° C., 4 ° C.) at a sheet thickness of 200 μm was used.
The sheet was formed by changing the temperature (0 ° C, 60 ° C), and the physical properties were measured.
The measurement results are shown in Table-3.

Comparative Example 5 With respect to the same composition as in Comparative Example 2, the sheet forming method was a combination of a mat roll and an air knife method, and the roll cooling temperature (20 ° C., 4 ° C., 4 ° C.) at a sheet thickness of 200 μm.
The sheet was formed by changing the temperature (0 ° C, 60 ° C), and the physical properties were measured.
The measurement results are shown in Table-3.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

As is clear from the above results, the highly transparent polypropylene sheet of the present invention exhibits high transparency and excellent workability and moldability even when the roll cooling temperature is lowered, and no odor is generated during sheet molding. It is a good one.

[0048]

EFFECT OF THE INVENTION The highly transparent polypropylene sheet of the present invention is excellent in transparency and processability and is suitable for food containers,
It is suitable for medical instruments, physics and chemistry equipment, etc.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C08K 5/521 KFM C08K 5/521 KFM 5/56 KFQ 5/56 KFQ

Claims (1)

[Claims] 1. (a) 100 crystalline polypropylene resin
0.01 to 5 parts by weight of at least one selected from the group consisting of alkali metal carboxylate, alkali metal β-diketonate and alkali metal β-ketoacetic ester salt, and (c) General formula (I) of [Chemical formula 1]: (In the formula, R ₁ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ and R ₃ represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and M represents
A metal atom of group III or group IV of the periodic table is shown,
X represents HO- when M represents a metal atom of Group III of the periodic table, and O = or (HO) ₂ -when M represents a metal atom of Group IV of the periodic table. Show. 0.01 to 5 parts by weight of at least one of the cyclic organic phosphoric acid ester basic polyvalent metal salt represented by the formula (4), and (d)
[Al ₂ Li (OH) ₆ ] _n X.mH ₂ O (II) (wherein X is an inorganic or organic anion, and n is an anion (X)) A valence, m is an integer of 3 or less.), A lithium aluminum complex hydroxide salt compound,
A highly transparent polypropylene sheet, characterized by being compounded with 0.02 to 0.1 part by weight and formed into a sheet.