JPS62178343A - Polyolefin laminated film and manufacture thereof - 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] [Industrial Field of Application] The present invention is characterized by its nine-handed tearability (hereinafter referred to as "hand-tearability"), impact resistance, and dispenser (cutting tool) properties when processed into an adhesive tape. The present invention relates to a laminated film that has excellent tearability with a cutting blade (hereinafter referred to as dispenser cuttability) and a method for producing the film.

[Conventional technology]

Conventionally, various techniques have been proposed for the purpose of imparting hand-cutting properties or dispenser-cutting properties to adhesive tapes and the like using polyolefin films such as polypropylene (hereinafter abbreviated as PP) as a material.

For example, a film uniaxially stretched in one width direction (for example, Japanese Utility Model Publication No. 50-16053), a laminated film of a biaxially stretched film and a film uniaxially stretched in the width direction (for example, Japanese Utility Model Publication No. 50-41271) ), and examples where dispenser cutability is improved by using a film containing 25 to 35 wt4 of petroleum resin added to polypropylene (for example, Japanese Patent Laid-Open No. 74774/1983) ), examples using polypropylene copolymers with low intrinsic viscosity (for example, JP-A-57
-96858).

[Problem that the invention seeks to solve]

All of the conventional methods for improving hand tearability reduce impact strength when used as an adhesive tape.

It had the disadvantage that it could not be used as a packaging tape or the like that would be subject to strong impact loads. Also, Jikko Sho 50-16
In the case of Publication No. 053 and Japanese Utility Model Publication No. 50-41271, the hand-cutting property is improved, but the horns tend to stretch in the longitudinal direction of the film, and the dispenser cutting property is not sufficient. In the case of JP-A No. 58-74774, the dispenser cuttability was not sufficient, and the directionality when cutting with two hands was not linear and random, which was also a problem.

The object of the present invention is to solve the above-mentioned problems and provide a good hand-cutting film and a method for producing the film.

[Means for solving problems]

The present invention mainly consists of 2 petroleum resins of 10 to 50 wt.% and polyolefins of 70 to 90 wt.%, and the polyolefin has an ethylene component and a propylene component of 0.5 to 50 wt.%, respectively, based on the sum of the weight of the petroleum resin and the weight of the polyolefin.
A biaxially oriented layer (A) consisting of a composition having a weight ratio of 20 to 89.5 wt % and a petroleum resin of 0 to 20 wt % and a polyurethane resin on one side.
The biaxially stretched layer (B) consisting of a composition mainly containing 0 to 100 wt% is laminated, and the ratio of the propylene component of one layer (B) (Wtl is the ratio of the propylene component of the layer (A)) -1 layer with more than 5 wt% of tl (B)
has a thickness of 0.8μ or more, and the thickness ratio of layer (B) to the sum of the thicknesses of two layers (A) and layer (B) (hereinafter abbreviated as (A) + (B) thickness) (((B) ) / [(A)+(B
)) 1x100 ) 1-40% IC 2 layer (A)
and the birefringence of layer (B) are ΔnA and ΔnB, respectively.
It is characterized by Lum.

First, the second layer (A) will be explained. What is petroleum resin?

It refers to a polymer obtained by catalytic polymerization of a monomer obtained by thermal decomposition of petroleum, or a hydrogenated product of this polymer, and generally includes cyclopentadiene, styrene, methylstyrene, etc. l Vinyltoluene, i/dene, methylindene, phtadiene, imprene, piperylene.

It is composed of monomers such as benchrene. The polymer may be a homopolymer or a mixture of one of these polymers, or a copolymer of several types.

Polyolefin is a polymer whose main components are ethylene and propylene, and may also contain other components such as butene, pentene, hexene, and 4-methylpentene.

Ethylene component color is ethylene monomer + CH2-CH2+
Specifically, polyethylene and/or copolymers with other monomers (ethylene-propylene copolymers, ethylene-butene copolymers, random and block copolymers, etc.) are mentioned. It will be done.

The propylene component is propylene monomer CH.

■ It is composed of 1+CH-C12+, specifically polypropylene and/or copolymers with other monomers (ethylene-propylene copolymer, butene-propylene copolymer, etc.) in random or block form. copolymers, etc.).

The polypropylene mentioned here may be any known polypropylene;
(abbreviated as I) preferably has 9 layers or more, more preferably 9 layers or more.

In addition, the melt flow index at 230°C (hereinafter M
(abbreviated as I) is preferably in the range of 1 to 20 g/l 0 min.

Polyethylene may be low density, high density, linear low density polyethylene, etc.

High-density polyethylene with a density of 0.930 or more (preferably 0.940 or more) or linear low-density polyethylene is particularly preferred. Further, by using polyethylene having an Ml of 1 or more, a semi-gloss glossy film can be obtained.

In addition, as for the copolymer containing an ethylene component or a propylene component here, + CH2-CH2→n≦
The ethylene component of 2, that is, the random ethylene component (
(hereinafter abbreviated as ethylene component processing) Preferably, ethylene-
The ethylene component of the propylene random copolymer 2, that is, the block-like ethylene lower component (hereinafter abbreviated as ethylene component (2)) is preferred.

Examples include ethylene-propylene copolymers.

The styrene component of EPRC is preferably 0.5 to 1 wt%, more preferably 1 to 5 wz%, and the MI at 230°C is preferably 1 to 20. More preferably, the number is in the range of 4 to 20. The ethylene component of EPBC is preferably 7
~50wt%, more preferably 15-40wt%, 2
MI at 30°C is preferably 1-20. More preferably 4
A value in the range of ~20 is good.

Note that other polymers may be mixed as long as the characteristics of the present invention are not impaired. Of course, known additives such as heat stabilizers, antioxidants, crystal nucleating agents, stabilizing agents, antistatic agents, anti-blocking agents, viscosity modifiers, light stabilizers, etc. may be added.

Wt of ethylene component and propylene component in layer (A) below
1 represents the content of the ethylene component and propylene component relative to the sum of the weight of the petroleum resin and the weight of the polyolefin in the first layer (A).@ Next, the first layer (B) will be explained.

What is the petroleum resin linolefin in layer (B)?

m (A) Similar to (A), the polyolefin preferably has a propylene component of 80 to 100 wt% based on the sum of the weight of the petroleum resin and the weight of the polyolefin. The ninth layer (B) contains two petroleum resins and a propylene component within a range that does not impair the characteristics of the present invention.

Other components 1 For example, other α-olefins other than the propylene component and known additives shown in layer 1 (A) may be added.

As an a-olefin other than the propylene component.

Particularly preferred is ethylene, and its content is not particularly limited, but is preferably 20 wt% or less based on the total weight of the polymer in the first layer (B).

In addition, the wtl of the propylene component in one layer (B) is
) represents the content of propylene component based on the total weight of the polymer.

Further, it is preferable that one petroleum resin is added to the first layer (B) because the cut portion will not whiten.

The laminated film of the present invention has good one-handed tearability, impact resistance, and dispenser cuttability.

In order to obtain such properties, (A) in the laminated film should contain -10 to 30 wt% (preferably 12 to 25 wt%) of petroleum resin.
wtl) and polyolefin/70 to 90 wt% (preferably 75 to 88 wt%), and the polyolefin L/7 (n is 0% to the sum of the weight of the petroleum resin and the weight of the polyolefin, respectively). .5-50
wt, mass (preferably 5 to 48 wt%) and 20 to
89.5 wt (preferably 40 to 83 wt) layer (A) is coated with petroleum resin 0 at least on one side.
~20 w<% (preferably 1-10 wt%).

More preferably 2 to 5 wt%) and polyolefin 80
~100 wt% (preferably 90~99 wtl, more preferably 95~98 wt%), and the polyolefin preferably has a propylene component of 80~100 wt% based on the sum of the weight of the petroleum resin and the weight of the polyolefin.
Layer (B) consisting of a composition having wt%, more preferably 90 to 99 wt%, even more preferably 95 to 98 w1%.
are laminated, and the ratio (wtl) of the propylene component in the first layer (B) is required to be greater than the ratio (wtl) of the propylene component in the layer (A) by at least 45+vt0. When the ethylene component is 0.5 wt% or more and less than 5 wt%, the ethylene component W is 0.5 wt% or more and less than 5 wt%, preferably 1 to 3 wt%, and the ethylene component → is 0 to 4.5 wt%. Particularly preferably, it is in the range of 0 to 4 wt%.

In addition, when the ethylene component of layer (A) is 5 to 50 wtl, the ethylene component is 0 to 5 wt%, preferably 0 to 3 wt%.
t%, ethylene component ■ is 0 to 5 owti, preferably 5 to
45 wtl, more preferably in the range of 10 to 40 wt%.

When the petroleum resin in layer (A) is less than 10 wt%, the laminated film has poor dispenser cuttability.

In addition, if the petroleum resin in layer 9 (A) exceeds 50 wtl, the components exceed 50 wtl.
When the content is less than 45,0.5 wt%, impact resistance decreases.

Also, the amount of petroleum resin added in each layer (B) is 2 Q
If it exceeds wtl, the resulting laminated film will have poor impact resistance. Furthermore, the value obtained by subtracting the ratio (wt, %) of the propylene component in layer (A) from the ratio (wtl) of propylene component in layer (B) is also calculated as the value for layer (A) of the laminated film of the present invention. When the birefringence of l (B) is expressed as ΔnA and ΔnB, respectively, 1.5≦ΔnB/Δ
It is necessary to satisfy the relationship nA≦7. In order to obtain even better hand cutability and dispenser cuttability, it is preferable that 1.8≦ΔnB/ΔnA≦6. Note that birefringence refers to the transverse refractive index "T" of each layer of the film.
The difference between D and the longitudinal refractive index 'MD' is 'TD'MII.The thickness of the layer (B) of the nine-layered film of the present invention is 0.8μ.
m or more, preferably 1 μm or more, and 1(A)
+ Thickness ratio of layer (B) to thickness of (B) ([(B)
/C(A) + (E) ) l xl 00 ) is 1
~40 section.

Preferably it should be between 2 and 38%. The thickness of layer (B) is less than 0.8.4 m or (A) of layer (B) +
If the thickness ratio to (B) is less than 1%, the impact resistance will be poor, and if the thickness ratio of 9 layers (B) to (A) + (B) exceeds 40%, the 9-layer tearability will deteriorate. . In addition.

The total thickness of the film is not particularly limited, but is 10 to 300μ.
m, preferably 15 to 200 μm, more preferably 1
It is in the range of 8 to 100 μm.

Note that when two layers (B) are laminated on both sides of layer (A), the thickness of layer (B) is the sum of both layers (B).

Next, an example of a single laminate film and a method for manufacturing the laminate film will be described.

pp, EPRC, IPBC, polyethylene, petroleum resin, etc. with an ethylene component of 0.5 to 50wt4. The composition of layer (A) mixed so that the propylene component was 895 to 20wtl9wt%, and pp1
The composition of layer (B) mixed with petroleum resin 0-80%2 was supplied to separate extruders, and melted and mixed at a resin temperature of 180-260°C. Afterwards, it is discharged from a slit-shaped mouthpiece by coextrusion method and cast onto a cooling drum with a surface temperature of 40 to 110°C to cool and solidify the laminated sheet.
After heating to 50° C., the laminated film is stretched 4 to 8 times in the longitudinal direction, and then the laminated film is fed into a tenter-type stretching device and stretched 8 to 12 times in the transverse direction. The best conditions for obtaining the laminated film of the present invention are that the transverse stretching temperature at this time is 145 to 165°C, preferably 150 to 163°C, and more preferably 155 to 163°C. If the transverse stretching temperature is lower than 145°C, the film will break frequently and stable stretching cannot be performed. Also.

Stretching unevenness tends to occur on the surface of layer (B), resulting in poor appearance.

After stretching in the transverse direction, the stretched film is heated at 150 to 162°C while relaxing 0 to 10% in the width direction as necessary.
by heat treatment for 3 to 10 seconds.

A laminated film of the present invention is obtained.

Layers (A) and (B) of the laminated film of the present invention are biaxially stretched layers stretched 4 to 8 times in the longitudinal direction and 8 to 12 times in the transverse direction, and have a birefringence ΔnA of 92 layers (A). is 2x 10-
3 or more 12 x 10-! Preferably, the birefringence of the 9 layers (8) is in the range of 10.10-.A.104 or more.
It is preferable that it is in the range below.

In addition, in order to obtain the effects of the present invention, layer (B) must be laminated on at least one side of layer (A),
Layer CB) on both sides of the two layers (A) to improve adhesion to the clips of the stretching roll and tenter set stretching equipment during film formation.
may be laminated.

Furthermore, the film of the present invention was subjected to corona discharge or plasma treatment under air, carbon dioxide gas, nitrogen gas, argon gas, etc., alone or in a mixed gas, to reduce the surface tension by 35 dy.
The surface adhesion may be improved by increasing ne/■ or more, or conversely, only one side may be coated with a release agent.

Further, as the polyethylene added to the first layer (A) and (B), polyethylene having a melt index of less than 1 may be used within a range that does not impair the characteristics of the present invention.

By adding a polymer that is poorly compatible with polypropylene, or by adding calcium carbonate, talc, dolomite, zeolite, kaolin, etc. to layer (A) or layer (B), the surface of layer (A) or layer (B) By embossing the film, it is possible to impart Ktli properties to the film, or to make it into a semi-gloss film like a so-called mending tape.

Alternatively, instead of adding the additives directly to the two layers (A) and (B) as described above, the polyolefin layer to which the above additives have been added is laminated to the two laminated films of the present invention within a range that does not impair the characteristics of the present invention. By the way.

It is also possible to impart drawability or to make a semi-gloss film. When processing the laminated film of the present invention into an adhesive tape, the film may be coated with an adhesive layer having pressure-sensitive adhesiveness at room temperature, such as polyacrylic acid ester. Laminate adhesive layers such as Of course, the lamination method is a solution or emulsion coating method.

There are solvent-free extrusion coating methods, but these methods are not particularly limited. Of course, a release agent may be applied to the surface opposite to the surface to which the adhesive is applied beforehand or after the adhesive is applied. The coating thickness is not particularly limited, but is usually 10 to 3
It is set to 0μ.

A polyolefin layer or the like may be interposed. The application methods are reverse roll method and gravure roll method.

Any method such as a kiss roll method, a doctor knife method, a curtain coater method, a fur/tin coater method, etc. can be used.

[Measurement method/evaluation method]

In addition, terms used in the present invention and evaluation methods of characteristics will be explained.

(1) Isotactic index refers to the batch ratio of the weight of the residue after extraction with boiling n-hebutane for 12 hours to the weight before extraction.

(2) Melt index Measured according to ASTM D 1258-57.

(3) Polymer density In a density gradient tube consisting of a water-alcohol mixed system.

Value measured at 25°C, expressed in F) g/I' units.

(4) Longitudinal refractive index nMD and lateral refractive index' of birefringent film
! The difference between TD and TD is "TD" VD, and the refractive index in the longitudinal and lateral directions of each layer of the laminated film was measured by the following method.

Double beam transmission interference microscope (Carl Zeiss
(manufactured by Jena) was used. The film is immersed in an inert liquid having a refractive index nI different from that of the layer to be measured, and at this time the difference in refractive index between the two is the maximum movement of the interference fringe of 0.2 to 0.8 wavelength. shall be given. The value of n5 was determined using an Atsube refractometer corrected for sodium D13. The measurement film is placed in the same direction as the measurement direction.
Thin sections of approximately 3 μm were used.

The film was placed in this liquid so that only one of the double beams passed through it, and its axis was placed against the stationary interference strip and perpendicular to the optical axis of the microscope.

Interference fringes were measured on this film using polarized light in the same direction as the measurement direction. The movement of the interference fringes is related to the refractive index and the thickness of the sample by the following equation.

d/D = (n n L ) t/λ where d is the distance between adjacent stripes n is the refractive index of the film in the measurement direction t is the optical path length at the point where d is measured ( In other words, the thickness of the sample) λ is the movement d of the interference stripes for each wavelength of light used for measurement, and a set of n and t values is obtained. Measurements were carried out in two types of liquids with different 0.01, and n was determined from two sets of n and t values.

(5) Hand-cutting property The 5# point was cut with scissors and twisted, and the stress at that time was read. There is a sufficient correlation between this stress and the hand tearability, and the hand tearability is expressed as shown in Table 1.

Table 1 (6) Using quantitative infrared absorption spectra (room temperature) of ethylene and propylene components, 8
40 am-' and 731at-' caused by ethylene.
, 720cIQ-' was determined by the calibration curve method.

The absorption of 72 o m-1 is due to the ethylene component ■,
The absorption of 31m-' is due to both the ethylene components, T and II.

It is preferable to use an infrared absorption spectrum measured at 160° C. to quantify the total ethylene component, since the effect of crystallinity is eliminated and absorption at 720 cIll-' disappears, improving measurement accuracy.

(7) Haze Measured based on JIS-K 6714 method.

(8) Impact resistance Charpy impact strength was measured as a characteristic value representing impact resistance.

Charpy impact strength is a value determined by a Charpy impact tester, and is expressed as a value obtained by dividing the energy E (?-am) required to cut a test piece by the sample width (cnl).

The calculation method for H is based on the following formula.

E=WR (cosβ-cos(1) W is the weight of the hammer (lcgL” is the distance from the center of rotation of the hammer to the center of gravity (elI+), α is the lifting angle of the hammer, and β is the weight of the hammer after cutting the specimen. It is the steady rest angle.

This is the stress (heel) at the time of cutting when the other end of the tape fixed at right angles to the serrated metal fitting is pulled toward the tape at an angle of 45° from vertically downward.

〔Example〕

The present invention will be explained below based on examples.

Example 1 pp (M18g/10min at 230°C, AE=97%
) and alicyclic petroleum resin ("Eaaore") as a petroleum resin.
z 5320″, manufactured by Esso Chemical) 25wt% and polyethylene (melt index at 190°C -8,
A resin obtained by adding and mixing 20 wt% of the petroleum resin (density = 0.945) and a resin obtained by adding and mixing 5 wt% of the petroleum resin to the PP were co-extruded at a resin temperature of 250°C using a T-die method, and
The mixture was cooled and solidified on a cooling cast drum maintained at 0° C. to obtain a laminated sheet. The laminated sheet was introduced into a hot air oven heated to 145°C.

It was stretched 5.0 times in the longitudinal direction and immediately cooled to below 40°C.

The laminated film was introduced into a tenter maintained at 158°C.
It was stretched 9 times in the width direction. Subsequently, both surfaces of the film were subjected to a corona discharge treatment, and the surface was treated to have a wetting tension of 39 dyne/at+.

The total thickness of the laminated film thus obtained was 33 μm, with one layer (A) having a thickness of 30 μm and one layer (B) having a thickness of 3 pm.
Met. Table 2 shows the film properties.

Add 0.1 dimethyl silicone thread release agent to one side of the film.
The adhesive tape was coated and dried to a thickness of μm, and then the reverse side was coated with polyacrylic acid ester as the main component. The properties of the resulting adhesive tape are shown in Table 2. From the same table, it can be seen that the adhesive tape using the laminated film of the present invention has excellent @Impact Resistance Dispenser Cutting Properties 9 Hand-cutting properties.

A laminated film was obtained in the same manner. Next, an adhesive tape was prepared and evaluated in the same manner as in Example 1. Although the hand-cutting properties were slightly lower, the tapes were excellent in dispenser-cutting properties and impact resistance.

Example 6 In Example 1, the layer (Shu raw material was mixed with ethylene component Swt%)
EpRa (2!+O℃ M work 10g/10min) 60
wt%, petroleum resin and PP each 20wt as in Example 1
%, but everything else was carried out in exactly the same way. When an adhesive tape was made using this laminated film in the same manner as in Example 1, the tape had a slightly lower hand-tearability, but had no practical problems and had excellent other properties.

Example 4 In Example 1, the raw material for layer (A) was 128w containing ethylene.
t% fox rBc70wt% (M19 g/1 at 250℃
0 min), E P RO with 4 wt% ethylene content (25
The experiment was carried out in exactly the same manner except that the same petroleum resin as in Example 1 was used at 20 wt%. When adhesive tapes were made using this laminated film in the same manner as in Example 1, they all had excellent if properties.

Example 5 The same petroleum resin and polyethylene as in Example 1 were used as ingredients 4w.
t% w P RO (M130 g/l at 230°C 0
When a mixture containing 30 wt% of 30 wt % of 30 wt % of the material was used as the raw material for layer (A), the process was carried out in exactly the same manner as in Example 1, and the hand cuttability and dispenser cuttability were good, but the impact resistance was slightly deteriorated. . However, there were no practical problems.

Comparative Example 1 When Example 1 was repeated except that the transverse stretching temperature was changed to 140° C., the other conditions were exactly the same, and the dispenser cuttability and impact resistance were good, but the one-handed cuttability was poor. Also, during film formation, film breakage occurred frequently.

Comparative Example 2 In Example 2, the mixing ratio of raw materials for layer 9 (A) was 20 wt% petroleum resin, 60 wt% polyethylene, and 20 wt% PP.
Ta.

Comparative Example 6 Same polyethylene as Example 1 3wt%9 petroleum resin 5w
A layer (
When the material was used in the same manner as in Example 1 except for the raw materials, the hand cuttability and dispenser cuttability were good, but the impact resistance was poor.

Comparative Example 4 25 wt% petroleum resin and pp (230
°C M work 2 () g/l 0 min, 97%) 80w
t% of the mixture was used as the raw material for layer (A), and the other conditions were carried out in exactly the same manner as in Example 1. Although the hand cuttability and dispenser cuttability were good, the impact resistance was poor. Ta.

Comparative Examples 5 to 6 Comparative Example 5 was carried out in exactly the same manner as in Example 1 (Comparative Example 6) except that the amount of petroleum resin added to layer (B) was changed to 30 wt%. , 6, it can be seen that the impact resistance is poor in both cases.

Comparative Example 7 (A) and CB) Both layers contained petroleum resin similar to that used in Example 2 and polyethylene: 8 gd of petroleum, 15 wt.
%.

It was.

Comparative Example 8 In Example 1, the transverse stretching temperature was 168°C, and layers (A) and CB
) was carried out in exactly the same manner except that the thickness of the film was 62 μm and 1 μm, but the film broke frequently and a laminated film could not be obtained.

By laminating two layers (CB) consisting of polyolefin containing a specific proportion of petroleum resin, ethylene component, and propylene component, and by specifying the amount of propylene component in both layers, it has excellent hand tearability and impact resistance. When a film is obtained and used as an adhesive tape, the following effects can be obtained.

(a) Dispenser cutability and hand-cutability.

It has excellent impact resistance and can be easily cut.

(2) t. An excellent method for producing a laminated film as described above could be provided.

Claims (2)

[Claims] (1) Petroleum resin 10-30wt% and polyolefin 70
The polyolefin is composed of a composition in which the ethylene component and the propylene component are 0.5 to 50 wt% and 20 to 89.5 wt%, respectively, based on the sum of the weight of the petroleum resin and the weight of the polyolefin. At least one side of the axially stretched layer (A) contains 0 to 2 petroleum resins.
A biaxially stretched layer (B) consisting of a composition mainly consisting of 0 wt% and 80 to 100 wt% of polyolefin is laminated, and the ratio (wt%) of the propylene component of the layer (B) is
is 5 wt% or more than the proportion (wt%) of the propylene component in layer (A), the thickness of layer (B) is 0.8 μm or more, and the sum of the thicknesses of layer (A) and layer (B). When the thickness ratio of the layer (B) to the layer (B) is 1 to 40%, and the birefringence of the layer (A) and the layer (B) is expressed as Δn_A and Δn_B, respectively, the ratio of the birefringence of the layer (B) and the layer (A) (Δn_B/
A polyolefin laminate film having Δn_A) of 1.5 to 7. (2) Petroleum resin 10-30wt% and polyolefin 70
~90 wt%, and the polyolefin is a layer consisting of a composition in which the ethylene component and the propylene component are 0.5 to 50 wt% and 20 to 89.5 wt%, respectively, based on the sum of the weight of the petroleum resin and the weight of the polyolefin. (A
) is laminated with a layer (B) consisting of a composition mainly composed of 0 to 20 wt% petroleum resin and 80 to 100 wt% polyolefin, and the laminate is heated 4 to 8 times in the longitudinal direction at 100 to 150°C. , 8 to 145 to 165℃ in the transverse direction
A method for producing a laminated film that is stretched 12 times.