JPS61137738A - Laminate - 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 A. Field of Industrial Application The present invention relates to a coextruded laminate having excellent gas barrier properties and good adhesion between resin layers. More specifically, ethylene-vinyl acetate copolymer saponified resin layer (A and polyvinyl chloride resin (Bl) are ethylene-vinyl acetate copolymer saponified resin layer (A) and polyvinyl chloride resin (Bl) are
Q: Regarding laminates laminated via adhesive resin layer (C) containing vinyl acetate copolymer B, Conventional technology Recent technological innovations in the food packaging industry 1i! IT is amazing.

For example, it is well known that thermoplastic resins such as polyvinyl chloride resins are used in food packaging for the purpose of reducing weight for hygiene, poor appearance, and transportation costs. However, these polyvinyl chloride resins have poor barrier properties against oxygen, carbon gas, etc., and are not suitable for long-term storage of foods, carbonated drinks, etc., so glass bottles, metal cans, etc. are still widely used. In addition, there are many problems such as pollution caused by empty cans being thrown on the streets and the cost required to collect the bottles, and there is a need to develop alternative packaging materials.

Saponified ethylene-vinyl acetate copolymer resins having an ethylene content of 20 to 55 moles have melt moldability, high transparency, and excellent gas barrier properties, making them excellent as food containers and packaging materials.

However, it has drawbacks in other physical properties, such as rigidity and moisture resistance, and is not satisfactory.

On the other hand, polyvinyl chloride resins have excellent moldability, balance between impact resistance and rigidity, hygiene, heat resistance, and economic efficiency, but they do not have sufficient gas barrier properties against oxygen and carbon dioxide. However, since it is not possible to store foods and beverages for long periods of time, its use as food containers and packaging materials is limited.

Therefore, in order to obtain food containers and packaging materials that combine the good gas barrier properties of saponified ethylene-vinyl acetate co-concrete and the excellent mechanical properties of polyvinyl chloride resin, layers of both resins are laminated. It is possible that However, these two resins have little affinity for each other, and it is impossible to obtain a solid laminate by thermal bonding.

Furthermore, it is not sufficient for the adhesive resin used in coextrusion molding to simply have adhesive properties; it must satisfy various performance requirements related to molding, such as heat resistance and melt viscosity.

Furthermore, JP-A-59-11251 discloses an ethylene-vinyl acetate copolymer with a vinyl acetate content of 10 to 70% by weight.
~99.9% by weight of polyolefin resin and unsaturated carboxylic acid primary is modified with its derivative, and a composition consisting of 50% to 0.1% by weight of polyolefin resin is used as an intermediate layer, and vinyl chloride resin, metal material, wood material, etc. This shows that it can be stacked.

Furthermore, JP-A-57-167326 discloses a method for completely adhering vinyl chloride resin and vinyl chloride resin or other base materials, with a vinyl acetate content of 30 to 65% by weight and a melt index of 10 to 400 g/10 min. Saponified product of ethylene-vinyl acetate copolymer and acid value 0.1-100
1 or 2 selected from the carboxyl modified products of the above ethylene-vinyl acetate copolymer which are 11qKOVg
It has been shown that by using it as an adhesive, it can be laminated with synthetic resins such as polystyrene and polyethylene, metals, cellulose-based natural materials, etc. by thermocompression, extrusion, etc.

However, none of the above-mentioned adhesive resin compositions HYW is shown to be used for lamination with a saponified ethylene-m-*vinyl copolymer. The ethylene component is used as the adhesive resin layer of the laminate made of a combination of 11 types of resins.
When a copolymer consisting of a vinyl acetate component and an ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride component is used, (depending on the combination of the koji layer resin (although it strongly adheres to the 8 layer resin), , (B) It is common that it does not adhere at all to the layer side, or conversely (it has good adhesion to the koji layer resin, but does not adhere to the 4-no resin. For example, polyolefin and etele/-acetic acid Atomer NF-500 (trademark, Mikata Sekika), which is effective as a coextrusion adhesive resin with saponified vinyl monomers and is used industrially, does not adhere to polyvinyl chloride resin at all. The quality of the resin layer is determined individually depending on the combination of adherend layers.The problem that OC Ming aims to solveIn view of this situation, the present inventors developed an ethylene-vinyl acetate copolymer. We examined the necessary properties of coextruded adhesive resins of saponified coalescent products and polyvinyl chloride resins, especially interlayer adhesion performance.
As a result of intensive study, this invention was not invented.

Means for Solving Problem D9 The present invention provides an adhesive resin (Q Through e, ethylene component content 20-55 mol%
According to the present invention, the effects of the OE1 invention, which is a laminate of a saponified ethylene-vinyl acetate copolymer (5) and a polyvinyl chloride resin (B) with a saponification degree difference of 90 or more, are achieved. It is possible to obtain a t&layer body with excellent properties, mechanical properties, and gas barrier properties. Next, the laminate obtained by the present invention is extremely useful as food containers and packaging materials.

F. More detailed explanation of light The greatest feature of the present invention is that (as the adhesive resin of the q layer, ethylene component - vinyl acetate component - ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride component - styrenic vinyl compound component) The purpose is to use a co-weighted body.

Ethylene component used in the present invention - Vinyl acetate component - Ethylenically unsaturated carboxylic acid or the carboxylic anhydride component -
The vinyl acetate component of the copolymer consisting of a styrenic vinyl compound component ranges from 15 to 40 weights. The same component is 1
If the weight is less than 5, the adhesion to polyvinyl chloride resins will not be sufficient, and the object of the present invention will not be met. However, if the weight exceeds A4040, the resin becomes too soft and problems such as wavy patterns on the molded product and uneven thickness of each layer tend to occur, so this is not recommended. The content of carboxyl groups due to ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride component is 0.0
1-1. s me q/g. 0.01meq
/g, not only polyvinyl chloride resin but also
This is not recommended since the adhesion to the saponified ethylene-vinyl acetate copolymer will decrease.

Even if it is introduced in excess of 1.5 meCV'g tl-, the effects such as adhesiveness will not only be saturated, but also be likely to cause discoloration, off-odor, putty, etc., so this is not recommended.

Although there are no particular limitations on the method for producing the copolymer used in the present invention,
A conventional graft polymerization method is used in which an ethylenically unsaturated carboxylic acid or carboxylic acid anhydride and a styrenic vinyl compound are grafted onto an ethylene-vinyl acetate copolymer, for example, in the presence of a radical polymerization initiator.

Ethylenically unsaturated carboxylic acids or carboxylic acid anhydrides include, for example, acrylic vinyl monomers such as acrylic acid and methacrylic acid, or, for example, maleic acid, maleic anhydride, 77-luic acid, itaconic acid, and itaconic anhydride. Examples of the acid include α,β-unsaturated dicarboxylic acids and their anhydrides, and it is particularly preferable to use maleic anhydride. Examples of the styrene-based vinyl compound include ester, p-methylstyrene, α-methylstyrene, etc., and it is particularly preferable to use styrene.0 The amount of the ethylenically unsaturated carboxylic acid or carboxylic acid anhydride used , a ratio-modified copolymer obtained by graft copolymerizing a styrenic vinyl compound and an ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride contains 0.02 to 2 meq 7'g 1 preferably 0 as a carboxyl group.
．． The amount of styrenic vinyl compound to give 2 to 1.0 meq/H is about 0.8 to 1.5 to this ethylenically unsaturated carboxylic acid or carboxylic acid anhydride.
The amount is twice the molar amount, preferably 1.1 to 1.4 times the molar amount.

The adhesive resin used in the present invention preferably has an ethylene component, a vinyl acetate component, an ethylenically unsaturated carboxylic acid, or a carboxylic acid anhydride that satisfies the following formulas (I) to (V). It is an adhesive resin composition in which a copolymer (X) consisting of a styrene/vinyl compound component and a copolymer (Y) consisting of an ethylene component and a vinyl acetate component are completely blended.

IVx-Vyl ≦0.25 − (1) 0.15≦
IVx-Wx-N'y-Wyl≦0.40 +++
(If)0.01≦Cx-Wx≦L5...
(II) 1゜O≦n −Sx/Cx≦2.0 −
<N>0.1≦Wx/Wy≦10 − (V)
However, vX: vinyl acetate component content of copolymer (X) (
weight fraction) vy: vinyl acetate component content (weight fraction) of copolymer (Y) Cx: ethylenically unsaturated carboxylic acid or carboxylic acid anhydride component content (me q/) of copolymer (CX) g) SX; styrenic vinyl compound component content (m-mole/g) of copolymer CX) Wx, copolymer (X)
Blending amount (weight fraction) Wy; Blending amount of copolymer (Y) (
Weight fraction) n; number of carboxyl groups contained in one molecule of the ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride n-8 When X/Cx is less than 1.0, moldability is relatively reduced. , and the adhesiveness with the polyvinyl chloride resin tends to decrease, which is not preferable. If the reverse Kn·Sx/Cx exceeds 2.0, the copolymer (η itself) becomes cloudy, which affects the appearance of the laminate, which is not suitable.

In particular, when maleic anhydride and styrene are used as a preferred example, these compounds are considered to be graft copolymerized to the copolymer (X) in the form of alternating copolymerization.

Furthermore, it is believed that the styrene used in excess with respect to maleic anhydride is solely grafted onto the copolymer (X)K.

The reasons why adhesive resin compositions satisfying the above-mentioned (I) to (V) are preferable are not necessarily clear, but include the presence or absence of an ethylenically unsaturated carboxylic acid or carboxylic acid anhydride component, the presence or absence of a styrene compound, Due to the difference in the content of vinyl acetate components, complex differences occur in the mutual affinity between (X) and (Y), and micro phase separation occurs in the adhesive resin when the two are blended or coextruded. Because of this, it is thought that it has a moderate affinity for polyvinyl chloride resin and saponified ethylene-vinyl acetate copolymer resin, and exhibits good adhesion and moldability for both. .

Next, in the present invention, the resin used as the layer is a saponified ethylene-vinyl acetate copolymer containing an ethylene component of 420 to 55 mol/l/% and having a degree of saponification of 90 mol or more.

If the content of the ethylene component is less than 20 moles, melt molding of the resulting saponified resin is difficult, and if it exceeds 55 moles, the gas barrier properties tend to deteriorate, which is not preferable. The degree of saponification of the vinyl acetate component is 90 molti or more. If it is less than 90 molty, not only the gas barrier properties will be low, but also physical properties such as heat resistance and water resistance will tend to deteriorate, which is not desirable.

(B) The polyvinyl chloride resin used for the layer is a hard polyvinyl chloride resin that does not contain a plasticizer, a polyvinyl chloride resin that is plasticized with Nisdel heptatalates, adipine esters, phosphoric acid esters, polyester plasticizers, etc. Graft copolymers obtained by graft polymerizing vinyl chloride in the presence of hard and soft polyvinyl chloride resins, ethylene-vinyl acetate copolymers and polyacrylic powder esters, and vinyl acetate.

Examples include copolymers with propylene, acrylic esters, vinylidene chloride, etc.

The laminate of the present invention can be obtained by a known method such as extrusion molding, injection molding, blow molding, etc. using a T-die, ring die, etc. using the resin as described above, and secondary molding can also be performed by vacuum or compressed air. . In this case, the polyvinyl chloride resin of layer (B) may be placed in the inner layer or the outer layer. M9 Laminate L Te H(A)-(C)-(B)
, (Bl(C1(A)-(C)-(B).

It can be made into a multilayer structure such as (C) -(B) -fc) -(A). Furthermore, the polyvinyl chloride resin layer (B) can have a multilayer structure if necessary. Furthermore, another resin layer (for example, a polyolefin layer such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, etc.) may be laminated on the laminate of the present invention thus obtained. You can also do it.

Obtained in this way: 71. Made of laminate! ! Although there is no particular limitation on the thickness of the r-no, it is preferable that the thickness of the (5) layer is 10 to 400 μm, the 0 layer is 5 to 300 μm, and the (13) layer is 50 to 3000 μm.

In addition, the adhesion between the layers of the obtained laminate was sufficient, and the barrier properties of polyvinyl chloride-based resin were very similar to those of saponified vinyl acetate copolymer. Useful as performance fc and mochi, food containers (cups, etc.), and bagging materials. 0 Below 34! The present invention is demonstrated by examples, but the present invention is not limited thereto.

Example 1 A graft copolymerization reaction of ethylene-vinyl acetate copolymer was carried out according to the following recipe using 20 as a reactor to obtain Q fC.

Ethylene-vinyl acetate copolymer 1500r Styre 15
42 Maleic anhydride 391 Benzoyl peroxide 6? xylene
1500117 First, ethylene-vinyl acetate copolymer and xylene were charged into a reactor, and stirring was continued for 1 hour at 115°C under a nitrogen atmosphere to completely dissolve the ethylene-vinyl acetate copolymer. Next, maleic anhydride and styrene were charged, and after stirring for 10 minutes, the polymerization initiator was dissolved in 100 d of xylene, and the next solution was injected with gold.
Continue the graft copolymerization reaction at 5-120°C for 2 hours.

After the completion of the polymerization reaction, 540 methanol was added while stirring.
After injecting 0d, the precipitated powdery material was removed and dried.

This product contains 24,5]1 amount of vinyl acetate component, left type 2
The MI measured with tsoy was 0.7f710min.

In this way, the obtained polymer
．． Ethylene component containing 2% by weight and Ml of 61/10 minutes - vinyl acetate component or Ranal! 1 body Y tot (X
)/(f)=4o/so K was blended. This composition contains 34% by weight of vinyl acetate component, carboxyl a feO,
l 6 meq/l, styrene component 0, Ill ■l-m-m01e/1 containing L tea, fe.

This adhesive resin composition was used as the q-layer resin, and was obtained by saponifying 99.6 mol% of the vinyl acetate component of an ethylene-vinyl acetate copolymer with a vinyl acetate content of 56 mol. ) = 0.96 (phenol/water = 8
In a 5/15 mixed solution, a saponified ethylene-vinyl acetate copolymer resin at 30°C, dt/f) was used as the layer resin, and a polyvinyl chloride resin containing no plasticizer was used as the (B) layer resin at the Gui temperature. Coextrusion was carried out at 200°C to obtain (B)/(
C)/4 A laminate of three types and three layers with a good appearance was obtained. The thickness of each layer is 30μ for (5), 20μ for (average), 20μ for 1G, and the peel strength between the cuts (180° peel, 200m/min) is good at 3.1 kp/z. AtsufC.

Comparative Example 1 Example 20 was polymerized using the following polymerization recipe using a reactor.
A friend who performs a graft polymerization reaction in the same way as 1.

Ethylene-vinyl acetate coelectrode e body 1500f Male anhydride/acid 31 benzoyl peroxinide 102 xylene
A graft copolymer containing 4,500 ml and a polymerization temperature of 120° C. and no ethylene component was obtained. This copolymer was coextruded in the same manner as in Example 1. The resulting laminate has a peel strength of 0.8
It's kcl/cm and has small irregularities all over, so it's practical and I want it to be hot fc.

Comparative Example 2 Polyethylene ("Mirason 45"
(manufactured by Mikata Sekika Co., Ltd.) (Y) t″(X)/(Y)=4
The ratio was 0/60. The vinyl acetate component content of the resulting composition was 9.8% by weight, with 0 carboxyl groups.
．． 16 meφ, the styrene component was obtained and the next set of oxides t(C
) As a layer resin, coextrusion is performed in the same manner as in Example 1.
The peel strength of the obtained virtual laminate was 0.1 kHz/cWI, which was the lowest.

Comparative Example 3 Ethylene-vinyl acetate copolymer (1) containing 199 parts by weight of vinyl acetate component in the polymer obtained in Example 1, consisting of ethylene component, vinyl acetate component, ethylenically unsaturated carboxylic acid anhydride, and styrene component. f&: (X) / (Y) =
Blend so that it becomes 2/9 s. Profit 0.007rn-
Contains mole/f.

Coextrusion was carried out in the same manner as in Example 1 using the obtained we composition as a q-layer resin. The peel strength of the obtained laminate was 0.
It is the next lowest at 2 kf/cm and ft.

Comparative Example 4 The same method as in Example 1 was carried out except that t75f was used for Stereph 1, and the vinyl acetate shoulder content was set to 2465.
Weight %, carboxyl group kO, 40 meq/? and styrene component 0.72 m-mole/P f, M
I is 0. '? A polymer (X) of 1/10 min was obtained, but it was significantly cloudy and could not be used as a zero-layer resin for this purpose.

Example 2 Containing vinyl acetate component "425% by weight and MI2, (
Instead of 1710 minutes of ethylene-vinyl acetate copolymer,
The content of vinyl acetate component is 33.5% by weight and M I
2. Of/10 minutes using ethylene-vinyl acetate copolymer and charging styrene and maleic anhydride -+i
In the same manner as in Example 1 except for changing t, the vinyl acetate component was 33% by weight and the carboxyl group was 0.42 m
A polymer (X) containing eφ, a styrene component and a maleic anhydride component in equimolar amounts, and an MI of 0.9 f and 710 minutes was obtained.

Ethylene-vinyl acetate copolymer (Y) with a vinyl acetate component content of 33.5% by weight (X) / (Y) = 5
Just in case it is mixed with 0750. The resulting next group acid has a vinyl acetate component of 33.3 weight s and a carboxyl group of 0.21 rll!
lq/2 content ratio.

[η , l=0.96 (phenol/water=8
5/15 mixed solution, 30°C, d4/9) cD ethylene-vinyl acetate copolymer saponified resin was used as the (3) layer resin, which was further plasticized with 35% by weight of diocmol 7-talate to form a polyvinyl chloride resin. k (B) layer resin was coextruded at a die temperature of 200°C, (B)/(q/4/
(C) / (B) We aim to create a beautiful laminate with three types and five layers.

The thickness of each layer is (5) layer 10μ, (koji layer 100μ, (C
) layer is 5μ, and the peel strength (T peeling 200m 1 minute) is good at 1.0 kf/crs.

Comparative Example 5 As obtained in Example 2, ethylene component - vinyl acetate component - ethylenically unsaturated carboxylic acid anhydride component - polymer CX having styrene component was added with ethylene-vinyl acetate containing 45% by weight of vinyl acetate component. Copolymer ■ (X) / (, Y) = 20
/80 and next.

This product contains a vinyl acetate component t' of 42.6% by weight and a carboxyl group kO, 08 meq/r.90 This adhesive resin composition was used as a 0-layer resin and coextruded in the same manner as in Example 2. However, the resulting laminate has a wavy pattern throughout, and is of low commercial value. Also, the peel strength is as low as 0.4 kflon, which is unbelievable.

Patent applicant RiRashi Co., Ltd. Same Takeda Pharmaceutical Company Limited

Claims (1)

[Scope of Claims] (1) Carboxyl group content by ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride component: 0.01 to 1.5
meq/g, contains a styrene vinyl compound component in a molar ratio of 1.0 to 2.0 to the ethylenically unsaturated carboxylic acid or carboxylic acid anhydride component, and contains a vinyl acetate component of 15 to 40% by weight. Through an adhesive resin (C) containing a copolymer consisting of an ethylene component, a vinyl acetate component, an ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride component, and a styrene vinyl compound component, the ethylene component content is 20 to 55%. A laminate obtained by laminating a saponified ethylene-vinyl acetate copolymer (A) and a polyvinyl chloride resin (B) having a mole % and an oxidation degree of 90% or more. (2) Copolymer (X) in which the adhesive resin consists of an ethylene component, a vinyl acetate component, an ethylenically unsaturated carboxylic acid or carboxylic acid anhydride component, and a styrene vinyl compound component
and a copolymer consisting of ethylene component and vinyl acetate component (Y
) in a manner that satisfies the following formulas (I) to (V). |V_x−V_y|≦0.25...(I) 0.15≦V_x・W_x+V_y・W_y≦0.40
...(II) 0.01≦C_x・W_x≦1.5...(III) 1.0≦n・S_x/C_x≦2.0...(IV) 0.1≦W_x/W_y≦ 10...(V) However, V_x; vinyl acetate component content of copolymer (X) (
weight fraction) V_y; vinyl acetate component content of copolymer (Y) (weight fraction) C_x; ethylenically unsaturated carboxylic acid or carboxylic acid anhydride component content of copolymer (X) (meq/ g) S_x: Content of styrene vinyl compound component in copolymer (X) (m·mole/g) W_x; Blending amount (weight fraction) of copolymer (X) W_y; Content of copolymer (Y) Blend amount (weight fraction) n: Number of carboxyl groups in one molecule of ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride