JPH0472343A - Polypropylene resin composition, film or sheet and container/packaging material using the same - Google Patents

Abstract

PURPOSE:To provide a polypropylene resin composition excellent in printability, coatability and transparency and suitable for films, sheets, containers and packaging materials by compounding an olefinic (co)polymer having specific bond units at side chains. CONSTITUTION:A composition excellent in printability and coatability comprises (A) polypropylene resin and (B) an olefinic (co)polymer having bond units of formula I or II, preferably an ethylene-vinyl ester copolymer (e.g. ethylene-vinyl acetate copolymer) radically copolymerized with a radically polymerizable monomer having bond units of formula I or II (e.g. vinyltrimethoxy silane or 3-methacryloxypropyltrimethoxy silane), and films, sheets, container or packaging materials prepared of the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a polypropylene resin composition with improved printability and paintability, a film or sheet, and a container/packaging material using the same.

[Prior Art] Conventionally, polypropylene resins have been widely used for various purposes because they have excellent mechanical properties, are inexpensive, and are easy to mold. However, it does not have polar groups or reactive active groups in its molecular structure, is a chemically stable substance, and has poor solubility in solvents, so it is problematic for secondary processing such as printing and painting. It is a resin with a lot of

Therefore, in order to perform secondary processing such as printing, various surface treatments are applied to the surface of polypropylene molded products, and other polymeric substances are added to polypropylene resin to make polypropylene It is necessary to improve the affinity of the surface of a molded product, and the surface of the molded product is activated by surface treatment or addition of other polymeric substances.

Examples of surface treatment methods for polypropylene molded products include:
Corona discharge treatment (Japanese Unexamined Patent Application Publication No. 53-71182) is known, but it has drawbacks such as insufficient sustainability of the surface activity obtained and furthermore, the type of ink that can be used is limited. In particular, with regard to UV-curable inks used in offset printing, corona treatment alone is insufficient to provide ink adhesion due to the persistence and strength of surface activity. It is painted. This method has drawbacks such as the expensive brimer and the increased number of steps, resulting in increased costs and problems in production control and quality control.

In addition, as a method of adding other polymeric substances to polypropylene resin, for example, a method of adding a polymer containing a polar group such as a carboxylic acid-modified polyolefin and a saponified ethylene-vinyl acetate copolymer (especially 1986
However, when the number of polar groups is increased, the compatibility with the polypropylene resin decreases and the physical properties of the molded product decrease. In particular, if the transparency decreases and becomes opaque, it cannot be used in food containers or stationery items that require transparency.

Furthermore, the molded product may sometimes experience delamination. Therefore, since there is an upper limit to the amount of polar groups introduced within which the physical properties do not deteriorate, there is also a limit to the effect of improving printability, and the requirements have not yet been met.

[Problems to be Solved by the Invention] An object of the present invention is to provide a polypropylene resin composition that can be printed without applying an undercoat primer, in particular can be printed with an ultraviolet curable ink, and has excellent transparency. .

[Means for Solving the Problems] In view of this situation, the present inventors have developed a polypropylene resin that can be printed with ultraviolet curable ink and has excellent transparency (without applying an undercoating flamer). , as a result of intensive research, -Si-O-C- or -Si-〇-
It was discovered that the adhesion between the polypropylene resin and the ink was improved by blending an olefin polymer or copolymer having H bonding units in the side chain, and the present invention was achieved based on this discovery.

That is, the present invention provides -Si-〇-C- or -Si-〇-H
An olefinic polymer or copolymer having a bonding unit in the side chain, preferably one Si-0-C- or -5j-
A propylene-based propylene-based product with improved printability containing an ethylene-vinyl ester copolymer into which 0-H bonding units are introduced by radical polymerization, especially an ethylene-vinyl ester copolymer with a vinyl ester content of 40 to 8Sij1%. It is used to print a resin composition.

[Constitution] The polypropylene resin used in the present invention includes propylene homopolymers, propylene and ethylene, and/or α-olefins having 4 to 12 carbon atoms (for example, Methylpentene-1
, octene), and may be used alone or in a mixture of two or more.

The olefin polymer or copolymer used in the present invention may be one having +[6 properties with the polypropylene resin. For example, ethylene homopolymer or its chlorinated product, propylene homopolymer or its chlorinated product,
Propylene and ethylene and/or carbon number 4-12
α-olefins (e.g. butene-1, hexene-1
Lantum or block copolymers with 1,4 methylpentene-1, octene), ethylene-vinyl ester copolymers (vinyl esters include, for example, vinyl formate,
Vinyl acetate, vinyl propionate, vinyl laurate,
vinyl benzoate) or its saponified product, ethylene-(meth)acrylic ester copolymer ((meth)acrylic esters include, for example, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, methacrylic acid ethyl), ethylene-(meth)acrylic acid copolymer ((meth)acrylic acid includes, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, and cinnamic acid). Among these, ethylene-vinyl ester copolymer is preferred. In particular, the vinyl ester content in the ethylene-vinyl ester copolymer is preferably 40 to 85% by weight. If the vinyl ester content is less than 40% by weight, the effect of improving printability will not be satisfactory, so it is not preferable. On the other hand, if the vinyl ester content t exceeds 85% by weight, the compatibility with the polypropylene resin will be poor and the physical properties of the composition will deteriorate, which is not preferable.

-Si-0-C- or -Si-O-H used in the present invention
As an olefin polymer or copolymer having a bonding unit in the side chain, -Si-0-C- or -Si-0
A product obtained by radically copolymerizing a radically polymerizable monomer having a bonding unit of -H during the production of the olefin polymer or copolymer, -Si-0-C- or -5f-
A product obtained by introducing a radically polymerizable monomer having a 0-H bonding unit into the olefin polymer or copolymer under graft polymerization conditions, -Si-0-C- or -Si-
A bifunctional compound having a functional group (A) consisting of a bonding unit of 0-H and another type of functional group (B) on the same molecule is combined with a functional group (C) that is reactive with the functional group (B). Examples include those introduced into the olefin polymer or copolymer having the following by reacting the functional group (B) with the functional group (C).

A radically polymerizable monomer having a bond unit of Si-0-C- or -Si-0-H, or -8t-0-C
- or a functional group consisting of a bonding unit of -Si-0-H (
The content of the bifunctional compound having A) and another type of functional group (B) on the same molecule is preferably 0.01 to 10% by weight in the polypropylene resin composition. If it is less than 0.01% by weight, the effect of improving printability is insufficient;
If it exceeds this amount, the fluidity of the polypropylene resin composition during molding will decrease, which is not preferable.

The radically polymerizable monomer having a bonding unit of 1-Si-0-C- or -SiO-H used in the present invention includes:
Examples include vinyltrimethoxysilane, vinyltrinidoxinane, vinyltris(2-methoxyethoxy)silane, and 3-methacryloxypropyltrimethoxysilane.

In addition, when introducing a radically polymerizable monomer having a bonding unit of -8i-0-C- or -Si-0-H, if necessary, a vinyl monomer other than the above-mentioned radically polymerizable monomer, such as vinyl acetate, vinyl propionate, etc. fatty acid vinyl esters, alkyl esters of acrylic acid or methacrylic acid such as ethyl acrylate, methyl acrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, methyl methacrylate, aromatic vinyls such as styrene, vinyl cyanides such as acrylonitrile, etc. may be used together.

A radically polymerizable monomer having a -Si-0-C- or -Si-0-H bonding unit can be introduced into an olefin polymer or copolymer using a melt grafting method using an extruder or in a solution. A general polymerization method such as a graft polymerization method can be used, and the polymerization method is carried out, for example, as follows.

That is, a radically polymerizable monomer having a bonding unit of -Si-0-C- or -Si-〇-H is added to an olefin polymer or copolymer in a suspended state, and the olefin polymer or copolymer is After the particles are made to absorb the radically polymerizable monomer having a bonding unit of -Si-0-C- or -Si-0-H, the temperature is raised and polymerization is carried out using a radical initiator. These radical initiators include benzoyl peroxide, azobisisobutyronitrile, t
-Butyl peroxybenzoate, t-phthyl peroxy (2-ethylhexanoate), diimpropyl peroxy carbonate, t-phthyl peroxy pivalate, t-butyl peroxy isopropyl carbonate, t-
-butyl lauryl peroxide, etc., which are usually added in an amount of 0.1 to 1 part by weight per 100 parts by weight of the radically polymerizable monomer having a -Si-O-C- or -Si-0-H bonding unit. Polymerization is carried out.

The polymerization temperature varies depending on the radical initiator used, but is from 60 to
The temperature is generally 130°C, and the resulting suspended Si
The olefin polymer or copolymer having -0-C- or -Si-0-H bonding units in side chains is separated from water, washed, and dried. At that time, an anti-blocking agent such as wax, silicone oil, silica, calcium carbonate, magnesium oxide, calcium stearate, etc. may be used, and the amount added is -9i-0-C- or -8i-0
Preferably from 0.1 to 100 parts by weight of an olefin polymer or copolymer having -H bonding unit in the side chain.
It is 10 parts by weight.

-Si-0-C- or -5l-O-H used in the present invention
Functional group (A) consisting of a bonding unit consisting of (A) and other types of functional groups (
A bifunctional compound having B) on the same molecule and a functional group (
Examples of the combination of the olefin polymer or copolymer having a functional group (C) reactive with B) include 3-glycidoxypropyltrimethoxysilane and carboxylic acid-modified polypropylene (an epoxy group and a carboxylic acid-modified polypropylene). (reaction with acid), 3-aminopropyltriethquinsilane and ethylene-ethyl acrylate copolymer (reaction with amine group and ester).

Other polymers may be blended within a range that does not impair the effects of the present invention. Examples of other polymers include EVAS 5BR
Rubbers such as SABS, PVC, chlorinated polyethylene, polyurethane, and polyester, and plastics may be mentioned.

Furthermore, commonly used pigments, stabilizers, lubricants, plasticizers, flame retardants, processability improvers, antistatic agents, crosslinking agents, etc. can be added to the polypropylene resin composition of the present invention.

In order to obtain the polypropylene resin composition of the present invention, the polypropylene resin, -Si-0-C or -Si-
The purpose can be achieved by uniformly mixing an olefin polymer or copolymer having bonding units ○-H in the side chain. Mixing methods include commonly used extruders, beef gingerol, kneader roll mills,
There is a method of kneading in a molten state using a mixer such as a Banbury mixer or a continuous mixer, but the mixture is mixed in advance using one of these mixers, and the resulting mixture is mixed in the same or other type of mixer. A more uniform treated product or composition can be obtained by mixing the resulting mixture using the same type of mixer or a different type of mixer. In addition, before carrying out these mixing operations, tri-blending is performed in advance using a mixer such as a drum tumbler or a Henschel mixer, and the resulting mixture is further melt-kneaded to obtain a more uniform treated product or composition. I can do it. Furthermore, some of these mixed components (composition components) are mixed in advance to produce a so-called masterbatch, and the resulting masterbatch (mixture)
and the remaining mixture components may be mixed.

The polypropylene resin composition obtained in this way or its compound (additive) can be shaped into a desired shape, such as a molded product,
Processing into films, sheets, multilayer laminates, etc. can be accomplished by conventional processing methods such as extrusion molding, injection molding, and calendering.

By such a method, containers and packaging materials with excellent printability can be obtained.

〔Example〕

Next, in order to further clarify the characteristics of the present invention, the present invention will be specifically explained using examples. In addition, the number of copies and percentages in Examples and Comparative Examples
All are on a weight basis. Further, processing methods, printing methods, and evaluation methods of the compositions used in Examples and Comparative Examples are as follows.

(1) Processing method of composition 90 parts of polypropylene resin (Union Polymer "A UP Polymer RBIIO") and one Si-0-C or -8
After triblending 10 parts of an olefin polymer or copolymer having 1-〇-H bonding unit in the side chain in a tumbler, it was made into a cross-wire pellet using a screw extruder (diameter 30 nm) to obtain the examples and comparative examples. A polypropylene resin composition was obtained. This composition (pellet) was extruded using a screw extruder equipped with a T-die, and
- Created a page.

(2) Transparency evaluation method To evaluate the transparency of a polypropylene resin composition,
When the sheet obtained in (1) was opaque, it was marked as ×, and when it was transparent, it was marked as ○.

(3) Sheet printing method One surface of the sheet obtained in (1) is subjected to corona treatment, and R
1 Using a tester (2-split roll, 0.15 cc volume), apply UV-curable ink (Daicure RT-7 Ai, Dainippon Ink Chemicals) and irradiate it with UV light at 10 m/cm under a UV lamp of 8 ow/cm. 1 pass) to obtain a printability evaluation test sheet.

(4) Printability evaluation method (adhesion) Testing was performed by cellotape peel test.

After applying commercially available cellophane tape and adhering it, it was peeled off.

○ indicates that there is no ink transfer to the cellophane tape at all; ○ indicates that the ink has been transferred to the cellophane tape on a portion of the adhesion surface and some ink remains on the sheet; and cases that the ink has been transferred to the entire surface of the cello tape. It was set as ×.

Example 1 In a magnetically stirred autoclave with an internal volume of 2 liters, 5 parts of vinyl acetate, 800 parts of distilled water, 1.6 parts of abbisisobutyronitrile (polymerization catalyst), and 1.6 parts of polyvinyl alcohol (dispersant) were placed. 1 part and 0.8 parts of sodium polyacrylate (dispersant), then the air in the autoclave was replaced with nitrogen, and 55 kg/cm of ethylene was added at 30°C.
After the injection was carried out, the internal temperature was raised to 65°C and suspension polymerization was carried out for 9 hours.The residual ethylene was released and the temperature was returned to room temperature and normal pressure, resulting in ethylene with a vinyl acetate content of 63%.
A vinyl acetate copolymer (1) (hereinafter abbreviated as EVA (1)) suspension was produced. To 840 parts of this EVA (1) suspension (resin content 25%), 0.7 parts of polyvinyl alcohol (dispersant), 84 m of methyl methacrylate (MMA), 3
-Methacryloxyfuropyltrimethoxysilane (MOP
SM) 6 parts, benzoyl peroxide (polymerization catalyst) 1
．． 8 parts were added and stirring continued for 2 hours at room temperature to absorb the monomer and initiator into the suspended particles. Thereafter, the temperature was raised to 75°C and polymerization was carried out for 5 hours. After washing the obtained particles, they were dried at 50°C for 24 hours to obtain modified EVA (A) 298.
I got the department. A polypropylene resin composition was evaluated using this modified EVA (A) as an olefin polymer or copolymer having a Si-0-C- or -Si-〇-H bonding unit in the side chain.

Example 2 75 parts of methyl methacrylate and vinyltriethoxysilane (VTSE) instead of 84 parts of methyl methacrylate and 6 parts of 3-methacryloxypropyltrimethoxysilane
Modified EVA was prepared in the same manner as in Example 1 except that 15 parts of modified EVA was used.
(B) 295 parts were obtained. This modified EVA (B) -
Polypropylene resin compositions were evaluated as olefin polymers or copolymers having Si-0-C- or -Si-0-H bonding units in their side chains.

Example 3 150 parts of vinyl acetate, 800 parts of distilled water, 1.6 parts of azobisisobutyronitrile (polymerization catalyst), 1.6 parts of polyvinyl alcohol (dispersant) and Add 0.8 parts of sodium polyacrylate (dispersant), then replace the air in the autoclave with nitrogen, and add ethylene to 62 kg/C at 30°C.
After press-fitting to 1i", the internal temperature was raised to 65°C, and
A time suspension polymerization was carried out. After releasing the residual ethylene and returning the temperature to room temperature and normal pressure, an ethylene-vinyl acetate copolymer (2) with a vinyl acetate content of 53% (hereinafter referred to as EVA (2)) was obtained.
) a suspension was formed. To 840 parts of this EVA (2) suspension (resin content 25%), 0.7 parts of polyvinyl alcohol (dispersant), 84 parts of methyl methacrylate, 6 parts of 3-methacryloxypropyltrimethoxysilane, benzoyl peroxide (polymerized 1.8 parts of catalyst) were added and stirring was continued for 2 hours at room temperature to absorb the monomer and initiator into the suspended particles. Thereafter, the temperature was raised to 75°C and polymerization was carried out for 5 hours. After washing the obtained particles, they were dried at 50°C for 24 hours to obtain 292 parts of modified EVA (C). This modified EVA (C) is converted into -Si-0-C- or -Si-0
Polypropylene resin compositions were evaluated as olefin polymers or copolymers having -H bonding units in their side chains.

Example 4 EVA (1) v suspension (resin content 25%) was used instead of 840 parts of EVA (1) suspension (resin content 25%), 84 parts of methyl methacrylate, and 6 parts of 3-methacryloxypropyltrimethoxysilane. ) 960 parts of modified EVA (D
) 293 copies were obtained. This modified EVA (D) was converted to -8j-
Polypropylene resin compositions were evaluated as olefin polymers or copolymers having 0-C- or -5j-〇-H bonding units in their side chains.

Comparative Example 1 Modified EV was produced in the same manner as in Example 1, except that 90 parts of methyl methacrylate was used instead of 84 parts of methyl methacrylate and 6 parts of 3-methacryloxyfurobyltrimethquine silane.
290 parts of A (E) were obtained.

This modified EVA (E) is converted into -Si-○-C- or -S
Polypropylene resin compositions were evaluated as olefin polymers or copolymers having i-0'-H bonding units in their side chains.

Comparative Example 2 EVA (1) of Example 1 was converted to -Si-0-C- or -
A polypropylene resin composition was evaluated as an olefin polymer or copolymer having Si-0-H bonding units in side chains.

Comparative example 3 Internal volume 2 'J? ) Vinyl acetate 250% in a flask
parts, 750 parts of distilled water, azobisisobutyronitrile (m
gold catalyst) 1.6 parts, polyvinyl alcohol (dispersant) 1
．． 6 parts and 0.8 parts of polyacrylic acid sorter (dispersant) were charged, the internal temperature was raised to 65°C, and suspension polymerization was carried out for 4 hours. When the temperature was returned to room temperature, a polyvinyl acetate (hereinafter abbreviated as PVAc) suspension was produced. To 840 parts of this PVAc suspension (resin content 25%), polyvinyl alcohol (dispersant>0.7 part, methyl methacrylate 84 parts, 3-methacryloxypropyltrimethoxysilane 6 parts, benzoyl peroxide (polymerization catalyst) 1. 8 parts were added and stirring was continued for 2 hours at room temperature to absorb the monomer and initiator into the suspended particles.Then, the temperature was raised to 75°C and polymerization was carried out for 5 hours.The resulting particles were a+ After that, at 50°C for 24 hours.
After drying for hours, 297 parts of modified PVAc was obtained. A polypropylene resin composition was evaluated using this modified PVAc as an olefin polymer or copolymer having a Si-0-C- or -Si-〇-H bonding unit in the side chain. However, because some layers of the sheet peeled off, it was impossible to evaluate the printability.

Comparative example 4 Content fjR2'J? ) 25 styrene in the flask.
0 parts, i distilled water 750 parts, azobisisobutyronitrile<
M gold catalyst) 1.6 parts, polyvinyl alcohol (dispersant)
1.6 parts and 0.8 parts of sodium polyacrylate (dispersant)
The internal temperature was raised to 65°C, and suspension polymerization was carried out for 9 hours. When the temperature was returned to room temperature, a polystyrene (hereinafter abbreviated as PS) suspension was produced. Add 840 parts of this PS suspension (resin content 25%) to polyvinyl alcohol (
1 agent), 84 parts of methyl methacrylate, 6 parts of 3-methacryloxyfurobyl trimethochine silane, and 1.8 parts of benzoyl peroxide (polymerization catalyst) were added, and stirring was continued at room temperature for 2 hours to dissolve the monomer. and initiator were absorbed into the suspended particles. Thereafter, the temperature was raised to 75°C and polymerization was carried out for 5 hours. After washing the obtained particles, they were dried at 50'C for 24 hours to obtain 297 parts of modified PVAc. A polypropylene resin composition was evaluated using this modified PVAc as an olefin polymer or copolymer having a bonding unit of 18l-○-C- or 1Si-0-H in the side chain. However, because some layers of the sheet peeled off, it was impossible to evaluate the printability.

Table-1 Table Examples Comparative Examples Stem Type Composition Olefin content (%) 37 37 Quantity (%)
7070 EVA EVA EVA EVA Trunk Type EVA EVA PVAc
PS composition Olefin containing N (%) 3737 0
0 amount (%') 701007070S
i Compound name MOPSM VTSE MOPSM
MOPSMSi compound amount (%) 2 5 2 3S
i Compound name Si compound amount (%) MOPSM MOPSM Other monomer name Other monomer 711%) MMA MMA MMA St Other monomer name MMA Other monomer 11%) 30 MMA MMA PP-based transparent composition Printability ○ ○ ○ ○ ○ ○ Q PP-based transparent composition Printability ○ ○ × × [Effects of the invention] The polypropylene-based resin composition obtained by the present invention can be printed without applying a primer for undercoating, and has particularly good printability with ultraviolet curable ink. Because it has excellent transparency, it can be used in a wide variety of fields. In particular, it is excellent as a container or packaging material when molded into molded articles, films, or sheets.

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Claims (1)

[Scope of Claims] 1. A propylene resin composition containing an olefin polymer or copolymer having a -Si-O-C- or -Si-O-H bonding unit in a side chain. 2. An olefin polymer or copolymer having a -Si-O-C- or -Si-O-H bond unit in the side chain has a -Si-O-C- or -Si-O-H bond. 2. The polypropylene resin composition according to claim 1, which is an ethylene-vinyl ester copolymer into which units are introduced by radical polymerization. 3. The polypropylene resin composition according to claim 2, wherein the vinyl ester content of the ethylene-vinyl ester copolymer is 40 to 85% by weight. 4. A film or sheet comprising the polypropylene resin composition according to claims 1 to 3. 5. A container or packaging material comprising the polypropylene resin composition according to claims 1 to 3.