JPS5837037A - Resin composition and laminated film prepared therefrom - Google Patents

Abstract

PURPOSE:To provide an extrusion coating resin compsn. having improved drawdown properties, adhesiveness, hot tack, extrusion workability and heat sealability, by mixing linear low-density polyethylene, low-density polyethylene and ethyleneic ionomer resin. CONSTITUTION:The titled resin compsn. is prepd. by mixing 20-70wt% linear low-density polyethylene (LLDPE) comprising an ethylene/3-10C alpha-olefin copolymer, 20-70wt% low-density polyethylene (LDPE), and 5-50wt% ethylene ionomer resin. Compared with LDPE, LLDPE has improved membrane strength, low-temperature properties, heat-sealing strength, contaminant sealing properties hot tack, but has lower melting viscosity. Thus, LLDPE has inferior film-forming properties and adhesiveness in extrusion coating process. The titled compsn. consisting of these three components has excellent extrusion workability, adhesiveness and heat-sealing properties.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin composition and a laminated film thereof, and more particularly, the present invention relates to a resin composition and a laminated film thereof, and more specifically, it has improved drawdown properties, adhesive properties, hot tack properties, excellent extrusion processability and heat seal properties, and is suitable for extrusion coating. The present invention relates to a resin composition for use in plastics, and a laminated film having a layer made of this composition on the surface layer.

Lin, a copolymer of ethylene and α-olefin, has recently been in the spotlight as the third poly-1-terene.
ear LOW Density Polyethyl
ene (linear low density polyethylene) (hereinafter LLDP)
It is abbreviated as E. ) is a normal low-density Vo9.1 Terene (hereinafter referred to as L
It is abbreviated as DPE. ), it has higher film strength, excellent low-temperature properties, high heat-sealing strength, and excellent performance in terms of contaminant sealing and hot tack properties, making it an alternative packaging material to LDPE. It has attracted attention as a film, and is processed into film exclusively by the inflation and T-Guy methods, and has been used as a single film and dry laminated film.
etc. are disclosed.

However, compared to LDPE, LLDPE alone has a lower viscosity when melted, and in extrusion coating processing,
Due to large neck-in and surging, thin film processability is poor, and adhesiveness is weak (perhaps due to the linear structure), making it practically unusable, making it difficult to use its excellent heat-sealing properties in laminated packaging materials. In order to make full use of it, a film such as an inflation film must be manufactured in advance and then bonded to a base material.

On the other hand, in order to take advantage of LLDPE's excellent heat sealing properties in the extrusion coating field, it is important to have good processability.

It is necessary to improve low-temperature sealing properties and adhesive properties, and one way to do this is to increase the viscosity when melted.

It is conceivable to blend LDPE with good neck-in and very little surging, but it is possible to blend LDPE with good neck-in and very little surging.
In terms of suitability for extrusion processing, the LDPE + LDPE two-component system eliminates the surging that was noticeable with LLDPE and improves neck-in to some extent, but when high-speed thin film processing is attempted, film breakage is observed and drawdown occurs. Furthermore, in terms of heat sealing properties, the sealing strength at the optimum sealing temperature was inferior to that of LLDPB alone, and there was little improvement in low temperature sealing properties or adhesion, so there were only shortcomings overall. It has become more prominent and the current LD
Compared to PE alone, there are no particular features, and nothing satisfactory has been obtained.

The present invention was made as a result of intensive research with the aim of solving the above-mentioned drawbacks.
Abbreviated as LDPE + ethylene-based iono-ionomer resin IR. It was discovered that the three-component blend composition of (1) has excellent extrusion processing properties, adhesive properties, and heat sealing properties as a resin for extrusion coating, leading to the present invention.

That is, the present invention firstly improves drawdown properties, adhesive properties,
The present invention provides a resin composition comprising the following components (II, (III), (til+)) as a resin composition for extrusion coating with improved hot tack properties and excellent extrusion processability and heat sealing properties.

(Linear low density polyethylene 20-70 which is a copolymer of leetelene and α-olefin having 3-10 carbon atoms)
wt%0 (II) Low density polyethylene 2 o”770 wt%,
.

(ii milliethylene ionomer resin 5-50 wtc
X.

In addition, the present invention is, secondly, a laminated film having a laminated structure of at least two layers, characterized in that at least one layer of the above-mentioned resin composition is disposed on the surface layer of the laminated film. The present invention provides a laminated film.

An essential requirement for the resin composition of the present invention is that LLDPE is blended with a partner of LDPE and IR to form a three-component system as a whole as a resin for extrusion coating.

The reason for this can be explained in detail as follows.

As mentioned above, LLDPE single octane has very excellent performance as a sealant after film forming, such as high heat sealing strength, good hot tack properties, and excellent contaminant sealing properties, but extrusion coating LDPE has large neck-in, poor adhesion, severe surging, and poor high-speed thin film processability, making it unpractical.
Although the LLDPE + -'LDPE two-component system, which is a blend of LLDPE + -'LDPE, has improved neck-in and surging as described above, it still has insufficient drawdown properties, and has poor adhesion and heat sealability compared to the case of LDPE alone. There are no discernible features in comparison, and there is almost no practical value.

Therefore, as a result of further intensive research, LLDPE+LDP
It has been found that a three-component resin composition in which IR is further blended with the E two-component system has extremely excellent performance for extrusion coating.

In other words, in the three-component system of LLDPE + LDPR + I R, the neck-in is slightly worse with the blend of E R, but
There is no particular problem in practical use, and high-speed thin film...film breakage during processing is reduced, drawdown property, which is one of the most important properties in practical use, is greatly improved, and adhesion to the substrate is also improved. It has been found that the low-temperature sealing properties and sealing strength in heat sealing properties are good, and the hot tack properties are close to those of LLDPE alone by blending IH and are significantly improved.

That is, L L D of the present invention 1, P E + L D
The P R+ I R3 component system has strong sealing strength, good contaminant sealing properties, and hot tack properties derived from the properties of LLDPE, and also has low temperature sealing properties and hot tack properties that reduce neck wear and adhesion due to LDPE and IH. The resin composition for extrusion coating has been improved, and in particular, the drawdown property has been significantly improved, and the resin composition for extrusion coating is well-balanced at a very high level, expressing only the strengths of each of the three components.

Next, each component in the three-component system (IJ'L L D P E
, (liJLDPE, (nlJ I R ratio).

+13 L L D P E is 20-70 wtX. Preferably it is 3°-50wtX; if it is less than 20wtX, the heat sealing strength will be low and the hot tack property will be poor (
Become. On the other hand, if the weight exceeds 70wt, surging will occur, drawdown performance will deteriorate, and neck-in will become large.

(11L DPE is 20-70 wtX, preferably 30-50 wtX; if it is less than 20 wt%, it will not be possible to improve drawdown properties and neck-in, and if it exceeds 70 wtX, LLDPE and IR The expression of properties is small (and it becomes not much different from LDP:E alone).

++l17I R is 5-50 wtX, preferably 1o-40 wtX, below 5 wtX, LLD
It is not much different from the PE+LDPE two-component system, but there are problems particularly with drawdown properties and hot tack properties. On the other hand, when FiOwt% is exceeded, ■'R and other LLI) PE.

Because the mixing and dispersibility with LDPR deteriorates, surging increases, neck-in also increases, and I
Since R itself is an expensive resin, the price of the three-component system as a whole increases, resulting in a situation where the performance is not commensurate with the cost.

Component (i) L'LDPE used in the present invention is, for example, a resin as shown in U.S. Pat. and butene-1, octene-1, hexene-1,4-methyl-pentene-1, etc. with 3 or more carbon atoms
It means a copolymer with 10 α-olefins. A copolymer of 1-terene and 1-octene gives preferred results in the present invention.

Further, it is preferable that the amount of α-olefin as a comonomer of ethylene in LLDPE is 1 to 2°wtX in the copolymer.

The mel and tod index should be 1.0P/10- or higher, preferably 20 to 159/105m, and considering the mixability and dispersibility with the remaining two components, LDPRlIR, there is a wide range of options for extrusion coating. becomes possible. MI is less than 1.09710 Whale, LDPE, IR
Mixing with other materials is poor, and drawdown properties are also poor. however,
When the MI exceeds 15 g/10 m, the viscosity during melting decreases and it tends to become difficult to maintain a uniform film at high temperatures.
This problem can be solved by lowering the MI. Further, the density (ASTMD-1505) is not particularly limited, but it is preferably 0.910 to 0.940 P/♂ from the viewpoint of processability, mixing dispersibility with LDPE, IR, etc.゛Similarly, the components used in the present invention (21L D P R
is a low-density polyethylene usually produced by a high-pressure process using a radical polymerization catalyst, with an MI of 2.0-15'i/10 m, preferably 4.
00-1 ('/10- is good, and this can also be selected from a wider range than the existing extrusion coating grade range, but it should be selected carefully taking into account the physical properties of the other two components, LLDPE, and IR. There is a need.

If the MI is less than 2.05'/10m, the effect of improving drawdown properties is small (if it exceeds 15P710m, the other two
The suitability for blending with ingredients becomes poor, and surging is likely to occur. There are no particular restrictions on density, but adhesiveness,
From the viewpoint of low-temperature sealability, preferably 0.910 to 0.
9239/- is good.

Similarly, IR refers to α, β-ethylenically unsaturated carboxylic acid partially or completely ionically crosslinked with 1-terene and metal ions, and optionally α.

It is a copolymer containing β-ethylenically unsaturated carboxylic acid ester as a constituent component.
9-315F) 6 is a known copolymer, and there are no particular restrictions on the production method or the type of metal ion, and other 2
There are no particular restrictions on the Ml, etc., as long as it has good mixing and dispersibility with the components LLDPE and LDPE. Furthermore, if the resin to be blended has terminal ionic crosslinks, ionic crosslinks are formed in the system such as an extruder during coating, and the resin coated on the base material eventually becomes a resin with ionic crosslinks. This also includes cases where there are.

Furthermore, there are no particular restrictions on the method of blending the three component resins constituting the present invention, and tri-blending may be used, or a method of blending the three component resins constituting the present invention may be used. You can also cork the mixture.

Second, the present invention provides a laminated film having a laminated structure of at least two layers, and the surface layer of the laminated film contains the following components: (1) 1-terene and an α-olefin having 3 to 10 carbon atoms. Linear low density boron 9.1 terene 20-70 which is a copolymer with
wt%, (j) Low density poly 1-terene 20-70wtX, 011J
The present invention provides a laminated film comprising at least one layer of a resin composition comprising 5 to 50% by weight of a polyethylene ionomer resin.

The base materials used for the laminated film of the present invention include paper,
In addition to cellophane and aluminum foil, films of various polymers can be used. Examples of polymers include:
polyvinyl chloride, polyvinylidene chloride, polystyrene,
Vinyl polymers such as polyacrylic acid esters, high-density poly9,-1-terene, medium- and low-density polyethylene, 1-terene monovinyl acetate copolymer, saponified products of 1-terene-vinyl acetate copolymer, 1 Terene monoacrylate copolymer,
Olefin polymers such as ethylene ionomers, polypropylene, polybutene-1, polyesters such as poly-1 terephthalate, polybutylene terephthalate, polyethylene terephthalate/isophthalate, nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, etc. Examples include polyamide and polycarbonate.

Further, the base material may be formed of the above-mentioned polymer alone, or may be formed of a mixture of two or more kinds of polymers.

The laminated film according to the present invention is composed of at least two layers, and the resin composition of the present invention is used as the R1 base material.
When expressed as S゛l + S2..., etc., the following layer configurations: R/S, R/8/R, R/ Ss/St, R/S
t/St/R, R/81/82/811, R/St
/St/Ss/R etc. are exemplified, and the base material layer may be formed of any number of layers as long as it is two or more layers.Furthermore, the base material layer may be stretched.

As the base material, when oxygen barrier properties are required, polyvinylidene chloride, a saponified product of 1-terene-mono-vinyl acetate copolymer, polyamide, etc. are selectively used. Moreover, when transparency, rigidity, etc. are required, it is preferable to use polypropylene as the base material.

In addition, in the laminated film of the present invention, the use of an anchor coating agent (ACj agent) for further improving adhesion between layers is not prohibited.

Various additives may be added to the resin composition as long as they do not adversely affect the effects of the present invention.The terms and evaluation methods used in the present invention will be explained below.

1) Neck-in: (T-die width) - (coat width of coating resin) Evaluation criteria: If it is 60 or less, there is no practical problem.

2) Drawdown: Set the flow rate so that the coating speed is 60 roe and the thickness is 20μ, increase the coating speed while keeping the discharge amount constant, and measure and evaluate the speed and thickness at which surging and film breakage occur.

Evaluation criteria: There is no practical problem as long as it can be processed to a thickness of 120%/sj+ or more and a thickness of 10μ or less.

3) Surging: Waving of the molten resin film during coating and uneven coating thickness.

4) Adhesiveness: Test the adhesive strength to kraft paper with a bond tester, measure and evaluate the pressure required for rupture and floating of the coated resin film.

Evaluation criteria: If it is 2.5b/- or more, there is no practical problem.

5) Heat sealing strength = 15III T of the sealing part of the width
- Peel strength was measured using a tensile tester (measurement temperature: 23°C). Tensile speed 300 Town heat sealing pressure 2. orl/cJ, time 1.0 sec.

Evaluation criteria: Strength at a sealing temperature of 160 C (unbleached kraft paper/sealing layer 20μ) There is no practical problem if the strength is 800p/15s+s or higher.

6 Heat sealability: Heat seal temperature ioo ℃ and 12
Evaluation criteria for sealing strength at 0°C: Two-layer strength: strength at 100°C and 120°C (unbleached kraft paper/sealing layer 20 μm) If the sum is 95097455 m or more, there is no practical problem.

7) Contaminant sealability: Apply vegetable oil to the sealing surface with absorbent cotton, seal as is, and measure and evaluate the sealing strength (in the case of unbleached kraft paper/Nul layer 20μ). Heat sealing conditions and measurement object are the same as when there are no contaminants.

Evaluation criteria: There is no practical problem if it is 600y/1511B or more.

8) Hot tack property: 2SllB width, length 3001oI
Cut out a sample (base material: 0-nylon, sealing layer 20μ), fix the upper end, and at the same time as opening the seal bar, apply a load of 459 to the lower end (T peeling), measure and evaluate the peeling distance of the seal part. .

Evaluation criteria: If the peeling distance is 1511) or less, there is no practical problem.

Next, the present invention will be explained in detail using Examples and Comparative Examples, and the extrusion coating process was evaluated using the following equipment.

Extruder: Sumitomo Heavy Industries 65jllllIφ extruder Screw: L/D-28, compression ratio -3,5, full flight type T-Die: Straight manifold die [Example 1-6
] As LLDPE, Dauretsu: x, x O-61f
i00.35 and 203.2 (manufactured by Dow Chemical Company),
Three components, L-188Fi and L-185OA (Asahi Dow polyethylene, manufactured by Asahi Dow Co., Ltd.) as LDPR, and Kobolene D-210 (manufactured by Asahi Dow Co., Ltd.) as IR, were tri-blended in a predetermined ratio, and the above 65118φ extrusion laminator was used. was used to evaluate extrusion coating suitability. Since the drawdown property was good, the adhesion and heat-sealing properties of the sample coated using unbleached kraft paper and O-nylon coated with a urethane AC agent as the base material were evaluated by the method described above. The results are summarized in Table 1, and it was found that the resin was very well-balanced and good.

[Comparative Examples 1 to 9] Dowlex 2o47 and ×0.61 as LLDPE
500.3Fi, L-1885 and L- as LDPE
115OA, IR as D-210, -n terene vinyl acetate copolymer (32 is abbreviated as EVA) as Q3
40 (manufactured by Asahi Dow Co., Ltd.) was triblended in the proportions shown in the table and evaluated in the same manner as in Example 1.

Comparative Examples 1 to 3 are three-component systems of LLDPE+LDPE+IR, and each of them is a three-component system of LLDPE! It is found that the resin is rich in LDPE, rich in LDPE, and rich in IR, and that, unlike Examples 1-6 and C1, the resin has poor extrusion suitability and heat sealing properties, making it unsuitable for extrusion coating.

Furthermore, it can be seen that Comparative Example 4 is made of LLDPE alone and is completely impractical for extrusion coating.

Comparative Examples 5 and 6 are two-component systems of LLDPE+LDPE, and Comparative Examples 7 and 8 are two-component systems of LLDPE+IH, and when compared with Examples 1-6, it can be seen that the performance is extremely inferior.

In Comparative Examples 1 to 8, if the extrusion suitability was very poor or if high-speed thin film processing was not possible, the subsequent evaluation of adhesiveness and heat rollability was omitted.

The results are summarized in Table 1.

Comparative Example 9 is a three-component system of LLDPE, LDPE, and EVA, but because the heat resistance of EVA is low, it is not possible to raise the resin temperature during extrusion processing, and it can be seen that the drawdown property is very poor.

are summarized in.

*1: Measured value of a sample processed at 80 m/m and 30μ. Reference value.

*2: Measured value 0 reference value when surging or membrane tearing occurs.

J: Not measured.

Table 2. Basic physical properties As described above, according to the present invention, LLDPE + LDPE + I R is used as the extrusion coating resin.
By using a three-component composition, extrusion coating suitability and heat sealing properties are balanced at a high level,
Very good, specifically, LLDPE can now be used in the extrusion coating field, as it is relatively inexpensive, has good drawdown properties, and has improved adhesion and hot tack properties. It has now become possible to provide an extrusion coating resin composition with excellent sealing properties and a laminated film thereof.

Sender: Asahi Dow Co., Ltd. Nippon Polyflex Industrial Co., Ltd. Agent Yutaka 1) Yoshio

Claims (1)

[Scope of Claims] (1) The following components: linear low-density poly-1-terene 20-70w, which is a copolymer of filT-terene and α-olefin having 3 to 10 carbon atoms.
tX. (i+4 low density poly 1-terene 20-70 wt 9g,
(iii) , c-terene ionomer resin 5 to 50
A resin composition consisting of wt%. (2) A laminated film having a laminated structure of at least two layers, in which the surface layer of the laminated film contains the following components: (1) A copolymer of 1-terene and an α-olefin having 3 to 10 carbon atoms. Some linear low density poly-1 terene 20~70w
t%, (11) Low density polyethylene 20-70 wt%, (i
ii) A laminated film comprising at least one layer of a resin composition made of c-terene ionomer resin 5 to 50 East Award.