JPS59229340A - Polyolefin double layer film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polyolefin bilayer films. More specifically, the present invention relates to a transparent polyolefin two-layer film that has a film screen that has a different level of slipperiness and whose slipperiness does not easily change over time.

Conventionally, in the field of packaging materials, the inner surface of the film has been designed to have moderate force slip properties in order to maintain packaging suitability, while the outer surface of the film has been designed to have mechanical adaptability during transportation and storage after packaging. Films with non-slip physical properties have been developed. For example, when forming a % film, the temperature of the die slip in contact with the inner surface of the film is made higher than the temperature of the die slip in contact with the outer surface of the film, and the temperature of the die slip is changed to ensure smoothness of the front and back surfaces of the film. A method of varying the slip properties of the front and back surfaces of the film is achieved by coextruding a resin with good slip properties on the side corresponding to the inner surface of the film and a resin with poor slip properties on the side corresponding to the outer surface of the film. Methods such as applying a non-slip material such as low-slip printing ink or hot-melt adhesive to one side of a regular film to make the front and back surfaces have different lubricity have been used.

Also known is a method in which a polyolefin resin containing a slip agent and a polyolefin resin not containing a slip agent are laminated into a film, and the resulting composite film is heat-treated (JP-A-Sho! 3-/JGr79). There is.

However, the method of varying the temperature of the die slips in contact with the front and back surfaces of the film causes roughness, for example, which is unfavorable for the appearance of the film, and the co-extrusion method requires the use of different types of resins, for example, Manufacturing is complicated and cost-effective, making it difficult to compete with general packaging materials.In addition, the method of applying non-slip material increases the number of film manufacturing steps, and requires special packaging materials. In the next method, which involves adding a slip agent and heat treatment, the film manufacturing process is complicated;
It was also disadvantageous in terms of cost and could not necessarily be a versatile film.

The present invention provides a transparent two-layer film consisting of a polyolefin resin containing finely divided feldspar, which is an inorganic filler, and a slip agent, and a polyolefin resin that does not substantially contain finely divided feldspar and a slip agent. The slipperiness on both sides is different.

Furthermore, they have discovered that this slipperiness does not easily change over time, and have completed the present invention.

That is, the gist of the present invention is a two-layer film made of polyolene, the film constituting one layer containing 0.7% by weight of finely powdered feldspar, slip agent O, OS-0
．． The present invention relates to a polyolefin WJ film characterized by comprising a polyolefin containing 3% by weight and a polyolefin.

In general, films obtained by laminating synthetic resins containing only slip agents and synthetic resins that do not exhibit a phenomenon called bleed or pluming, in which the slip agent flows from the resin layer containing the slip agent to the resin layer not containing it. It migrates over time, and it migrates even more quickly when heated, making the film surface of the resin layer that contains a slip agent slippery, and if left at room temperature for a long period of time, the slipperiness of both sides of the film may become significantly different. It was known.

In the present invention, by using finely powdered feldspar in addition to the slip agent, it has transparency, and the resin layer containing finely powdered feldspar and slip agent becomes easy to slip. It has been found that a resin layer that does not contain .

The reason why the bleeding of the slip agent is prevented by using finely powdered feldspar together is not clear in 1, but 2 is thought to be because the slip agent is preLsed by feldspar during its transfer through the resin layer. . Inorganic fillers other than feldspar (such as natural silica and talc) may have some effect, but are not desirable because they cause problems such as deterioration of the transparency of the film.

Synthetic silica cannot be used because adsorption of slip agents is difficult to occur and the slip agent migrates to the resin layer that does not contain a slip agent, resulting in a film having slipperiness on both sides.

To explain the present invention in detail, the polyolefin resins that can be used in the present invention include low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer. Mixtures of these resins and mixtures of these resins with small amounts of other resins such as polystyrene, polyvinyl chloride, etc. are used.

A combination of a polyolefin resin containing fine powdered feldspar and a slip agent (hereinafter referred to as "resin (A)") and a polyolefin resin without blending (hereinafter referred to as "resin")) even if they are the same resin. The effects of the present invention can be expected even with different types of resins.

The fine powder feldspar used in the present invention is calcium (Oa
), sodium (Na), potassium (K), and other aluminosilicate as the main components. Depending on the composition, there are types of potassium feldspar, sulfur feldspar, anorthite, plagioclase, etc. It is usually a mixture of these.

The feldspar used in the present invention may be in a mixed state as described above, and the proportion of each strain of feldspar may be %%, approximately 410 km north of Lake Ontario, Canada.
Feldspar containing a spreading layer produced from Nefton is preferred in terms of imparting transparency to the two-layer film.

The average grain size of the feldspar is ~10μ, preferably 3~tμ. To measure the average grain size, since feldspar is more tabular than mentioned above, it is observed under a microscope without considering the thickness, and the average value of the long side and short side is determined, and this is determined as the average grain size. did.

If the average particle size of feldspar is smaller than /μ, it will agglomerate, resulting in poor dispersibility in the resin, and will easily float in the air, causing environmental health problems.If it is larger than 70μ, it will not be blended into polyolefin. After being formed into a film, it gels and the appearance of the film becomes poor, so it cannot be used.

The amount of feldspar contained in the polyolefin resin (A) is 0, /j
- J weight tX, preferably θ0.2 to 80 weight,
If there is more than this amount, the blocking prevention effect will not occur,
If the amount is more than this, the transparency of the film will be impaired.

As the slip agent used with the above-mentioned feldspar, an aliphatic carboxylic acid amide is usually used. The melting point for an aliphatic carboxylic acid oxide! θ~/10℃ preferably 7
θ~? Saturated or unsaturated fatty acid amides in the range of 0° C. are used.

Particularly suitable are unsaturated fatty acid amides. For example, oleic acid amide (melting point (Mp): 2t°C).

Erucic acid amide (MP: /θ℃), ricinoleic acid 7S)” (MP: tr'c)%x' lucic acid 7,
% (MP; 22-27°C), stearic acid (M
P: 700°C), oxystearamide (MP2/θ!°C), and methylolamide (MP: 107°C). If the melting point is 710°C or higher, when formed into a film, the speed at which it bleeds onto the film surface is too slow, and the film does not have good lubricity, making it difficult to contribute to the opening property when it is made into a bag. . The melting point! θ℃
The table below shows excessive bleed 1. For example, during molding, it adheres to the surface of the take-up roll and is transferred to the film, causing poor transparency and giving a sticky feel. be.

The blending amount of the slip agent is 0.03 to 0.3% by weight, preferably 0.0t to 0.2% by weight. Otherwise, excessive bleeding may cause the film to become white.

On the other hand, polyolefin is usually used as it is to form a layer that is substantially free of finely divided feldspar and slip agents, but a small amount of finely divided feldspar (usually θ, /7% by weight or less), a slip agent (usually 0.03% by weight or less), and an inorganic filler such as silica may also be added. Regarding slipperiness, if the value of 00F (described later) is 0.4 or more, it does not exhibit slipperiness, and if oop is 0.4 or less, it indicates good slipperiness. In the case of the two-layer film of the invention, the % OOFO on one side of the film is less than or equal to 0O,4, and the %OFO on the other side is greater than or equal to 0OFO,4.

As a method of laminating resin body) and resin (B), A 8
- Polyolefin resin (A) and polyolefin resin (
B) A method of forming a film from each and interposing one of the above molten resins between both films to form a composite, or forming a film from one of the resins by an inflation method, a calendering method, or an HT-die method. Method 1: Co-extrude both resins using the inflation T-die method and melt-bond them inside the die or outside the die. Various methods such as a conjugation method are employed, and among these, the coextrusion method is the most preferred method in consideration of workability, ease of compounding, and reliability71+.

However, the thickness of the film is already determined depending on the various uses and can be difficult! ~3θOμ, for example, in the case of heavy packaging film for packaging fertilizers, etc./! θ~, 2 yo Oμ.

60~/　00　/j for film used for rice bags.

/# 1 for film used for sugar bags and base bags for about 1 person
A material having a diameter of about 0 to 70μ is adopted.

The ratio of the thickness of the resin (A) layer containing fine powdered feldspar and slip agent to the total thickness of the two-layer film is the thickness of the two-layer film,
It varies depending on the amount of fine powdered feldspar and slip agent added, and can be selected as appropriate, but it is preferable to add 0.6% or more to achieve uniform lamination, and if it is thicker than necessary, it will be disadvantageous in terms of cost. ! It is preferable to set it to θ% or less.

In the two-layer film of the present invention, the resin (A) is transparent and contains fine powdery feldspar and a slip agent, and the surface of the resin (A) is slippery.
) has no smooth surface. Moreover, this smoothness and transparency are difficult to change.

In addition, bags made from the polyolefin double-layer film of the present invention have different lubricity on the inner and outer surfaces of the bag.For example, when packaging fertilizer, the inner surface is slippery, making it suitable for packaging, and the outer surface is slippery. It is very convenient for transportation and storage because it is difficult to tear, and it has extremely high utility value as wood for various packaging bags.

The method of the present invention will be specifically explained in Examples, but the method of the present invention will be described in the following Examples K PE as long as it does not deviate from its gist.
It depends on what is specified.

In the same example, the evaluation of lubricity was based on the coefficient of static friction (OO
F). OOF is a friction angle tester.

The slip start angle θ was expressed as tan θ using a slider (manufactured by Toyo Seiki Co., Ltd.).

The smaller the 0QFO value, the smoother the 0'Q
? A larger value means less slipperiness.

Further, transparency was measured in accordance with ASTM D-1003-1,2T and expressed as haze (%).

Example/ Low density polyethylene (manufactured by Mitsubishi Chemical Corporation, Tubatic)
L-P/θQ, M work: θ, da 2/10 minutes, density g: o
, y, 2s y/cyl) Vc1 stone (average particle size, !μ, surface area com 4' n?/fr, Shiroishi Calcium ■% Pishimon feldspar, trade name: Minetx 2) θ,,
2 z wt CX and erucamide 0. /ko wt
% was added to obtain resin (A).

ll- Linear low density polyethylene (M process: 7fl/10 min, density 20, -22f/Cd% copolymerization component nibten-/1 copolymerization molecule: /θwtX) with resin (B) in two-layer T Die coextruder (■ Nippon Steel Corporation, ttg (resin (A)) t
Oe (resin (B)) extruded width / l jOtut
, clearance θ, two-layer die attached to ♂)
Resin temperature from K, 2 to 0 degrees Celsius, rotation speed of 91 degrees: re
: 3.2. 60g: Extrude downward at 2rr, p, m, extrusion amount θkg/hr, directly below T die/θ
A two-layer film with a thickness of 3 jμ was obtained by taking it off at a speed of 74 tons and m/min while rapidly cooling it in a six-water bath (water temperature 20° C.) provided at the position of the brim. The thickness of the resin (A) in the two-layer film was 10 μm.

Table 7 shows the lubricity and transparency of the obtained two-layer film after 10 g of time had elapsed.

Comparative Example/Example/Instead of feldspar), natural silica (J, 2t mesh 2 passage rate is 99.j%, surface area 2/~J, rd/
yr, manufactured by John Manville, trade name Varnish-Percloth)
A two-layer film was obtained in the same manner as in Example 12 except that .

The lubricity and transparency of the obtained two-layer film are shown in Table 1.

Comparative Example Example / except that synthetic silica (average particle diameter μ5 surface area: 22θrt?/yr, manufactured by Fuji Davison ■, trade name: Thyroid #7.2) was used instead of feldspar. A two-layer film was obtained in the same manner.

The lubricity and transparency of the obtained two-layer film are shown in Table 1.

In Example/Example/, low density polyethylene (
Manufactured by Mitsubishi Chemical Corporation, Tsubachik-L-1'/! 0. M engineering:, 2.02710 minutes, density: θ, ? , 2 , <y/
A two-layer film was obtained in the same manner as in Example except that 7) was used.

The lubricity and transparency of the obtained two-layer film after each passing time are shown in Table 1.

Table 15-Example 3-g Linear low-density polyethylene (M work (/0℃) 27971
0 minutes, density: θ, ri/rf/cd% copolymerization component nibten-/, copolymerization amount: 10wt%) 20 parts by weight and low density polyethylene (manufactured by Mitsubishi Chemical Corporation, Tubatic L-IF)
-/J/, M work: /,, 22710 minutes, density 20, 924 f/Cd) Average particle size: 3
．． 3μ, surface area: j 00 rr? 711F, manufactured by Fuji Deguison ■, product name: Cyroid $, 24t4t) /
WtX, Example/fine powdered feldspar/wtX,
and 3 parts by weight of erucic acid amide/77 wtX were mixed, extruded using a T-die extruder, and cooled with water to obtain a film of resin (B) of 3 jμ.

Next, as the resin (A), low-density polyethylene (manufactured by Mitsubishi Chemical Corporation, Tubatic LL-330゜M): /, 2
@O2710 minutes, density 20,? /rf/dl)
Finely powdered feldspar and erucic acid amylamide were added in the proportions shown in Table 3 and extruded using an ε-nator (manufactured by Sumitomo Heavy Industries, Ltd., laminator -90, screw diameter: ?orxv).
e%L/D-sz, T tie total length: 100θ1111,
T-die effective length: tOθ, slit width 2/fin), resin temperature (lip exit), 2! °C, screw rotation? /
/r, p6m, extrusion f -t, -2kg/hr, take-up speed 60m/min onto a film of resin CB) /θ
Laminated to a thickness of μ.

Table 3 shows the lubricity and transparency of the outer surface of the resin (A) and the outer surface of the resin (B) of the obtained two-layer laminate film after 100 hours.

-19- Comparative Example 3 A two-layer laminate film was obtained in the same manner as in Examples 3 to g except that in Examples 3 to 4, resin (A) VC feldspar and erucamide were not added.

Of this film! Table 3 shows the smoothness and transparency after θθ time.
Shown below.

Sender: Mitsubishi Chemical Industries, Ltd. Representative Patent Attorney Hase - (7 others) 20-

Claims (3)

[Claims] (1) A two-layer film made of polyolefin, one layer of which is made of fine powdered feldspar θ, ir
-, double 43. A polyolefin two-layer film comprising six polyolefins containing X% slip agent θ, 03 to 0.3%. (2) The polyolefin sand film according to claim 1, wherein the finely powdered feldspar contains nepheline. (3) The polyolefin two-layer film according to claim 1 or 2, wherein the slip agent is an aliphatic carboxylic acid amide.