JPS61137737A - 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 adhesive strength between resin layers.

More specifically, a saponified ethylene-vinyl acetate copolymer resin layer (A) and a polycarbonate (B) are combined with an adhesive resin layer (C) containing an ethylene-vinyl acetate copolymer that satisfies certain conditions. This invention relates to a laminate formed by coextrusion and lamination.

Technological innovation in the food packaging industry in recent years has been remarkable.

For example, it is well known that thermoplastic resins such as polycarbonate are being used for food packaging for the purpose of sanitary properties, beautiful appearance, and weight reduction to reduce transportation costs. However, these polycarbonate 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. As a result, there are many problems such as pollution caused by empty cans being thrown on the streets and the cost required to collect the bottles, which has hindered the development of alternative packaging materials.

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

However, there are many drawbacks in other physical properties, such as rigidity and moisture resistance, and it is not completely satisfactory.

On the other hand, polycarbonate, especially polycarbonate obtained from 4,4'dihydroxydiphenyl-2,2-7'' loban, has poor moldability, balance between impact resistance and rigidity, hygiene, heat resistance, and fragrance retention. Although it is excellent, it does not have sufficient barrier properties against gases such as oxygen and carbon dioxide, and food and beverages cannot be stored for long periods of time.
There are restrictions on its use as food containers and packaging materials.

Therefore, in order to obtain food containers and packaging materials that combine the good gas barrier properties of saponified ethylene-vinyl acetate copolymer and the excellent mechanical properties of polycarbonate resin, it is possible to laminate layers of both resins. Conceivable. However, these two phase resin layers have almost no affinity with each other, and it is impossible to obtain a laminate by mere thermal bonding.

Furthermore, it is not sufficient for the adhesive resin used in coextrusion molding to simply have adhesive properties; it must also satisfy various molding properties such as moldability, heat resistance, and melt viscosity. Furthermore, in JP-A-54-101883, a thermoplastic resin and a saponified ethylene-vinyl acetate copolymer are combined with a copolymer of ethylene and a monomer containing a carboxyl group or a substituent thereof, and an ethylenically unsaturated fatty acid or its anhydride. This shows that a modified copolymer obtained by chemically bonding can be used as an intermediate layer.

However, when a copolymer consisting of an ethylene component, a vinyl acetate component, and an ethylenically unsaturated carboxylic acid or carboxylic acid anhydride component is used as the adhesive resin layer of a laminate made of a combination of various resins, ( Depending on the combination of layer resins A) and (B), it may adhere strongly to layer resin (A) but not at all to layer resin (B), or vice versa.
) layer resin has good adhesion, but it is common that it does not adhere to (A) layer resin. For example, Atomer NF-500 (trademark, Mitsui Seki Kagaku), which is effective as an adhesive resin coextruded with a saponified ethylene-vinyl acetate copolymer and a polyolefin and is used industrially, does not adhere to polycarbonate at all. Therefore, the quality of the adhesive resin layer is determined individually depending on the combination of adherend layers.

C6 Problems to be Solved by the Invention In view of the above circumstances, the present inventors have determined the necessary characteristics of the coextruded adhesive resin of a saponified ethylene-vinyl acetate copolymer and a polycarbonate resin, particularly the interlayer adhesion performance. After careful consideration and extensive research, we have arrived at the present invention.

Means for Solving the D0 Problem The present invention provides an adhesive resin (C ), ethylene component content 20-55 mol%
This is a laminate in which a saponified ethylene-vinyl acetate copolymer (A) with a degree of saponification of 90% or more and a polycarbonate (B) are laminated.

E1 Functions and Effects of the Invention According to the present invention, it is possible to obtain a laminate having excellent interlayer adhesion, as well as excellent mechanical properties and gas barrier properties. For this reason, the laminate obtained by the present invention is extremely useful as food containers and packaging materials.

The greatest feature of the present invention is that the adhesive resin of the layer (C) is a copolymer consisting of an ethylene component, a vinyl acetate component, an ethylenically unsaturated carboxylic acid or carboxylic acid anhydride component, and a styrene vinyl compound component. I am there.

The vinyl acetate component of the copolymer consisting of the ethylene component, the vinyl acetate component, the ethylenically unsaturated carboxylic acid or carboxylic acid anhydride component, and the styrene vinyl compound component used in the present invention is in the range of 15 to 40 H. . If the content of the same component is less than 15, the adhesion to polycarbonate will not be sufficient, and the object of the present invention will not be met.

If it exceeds 40% by weight, it is not recommended because the resin becomes too soft and problems such as wavy patterns on the molded product and uneven thickness of each layer tend to occur. The content of carboxyl groups due to ethylenically unsaturated carbo/acid or the carboxylic acid anhydride component is 0.
．． 01-1°5meq/, sold by SI. 0.01meq
/ ,! If it is less than i+, the adhesion not only to polycarbonate but also to saponified ethylene-vinyl acetate copolymer will decrease, so this is not desirable. 1.5meq
/ I is not recommended because the effects such as adhesiveness will not only be saturated, but also cause discoloration, off-odor, putty, etc.

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 acrylic and nyl monomers such as acrylic acid and methacrylic acid, or maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, etc. Mention may be made of α,β-unsaturated dicarboxylic acids or their anhydrides, and it is particularly preferred to use maleic anhydride. Examples of the styrenic vinyl compound include styrene, p-methylstyrene, α-methylstyrene, etc., and it is particularly preferable to use styrene.

If the ethylenically unsaturated carboxylic acid is used, the amount of the carboxylic acid anhydride used in the modified copolymer obtained by graft copolymerizing the styrene vinyl compound and the ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride is , 0.02-2 meq/g as carboxyl group, preferably 0
．． 2~1.0 meq/,! The amount of the styrenic vinyl compound is approximately 0.8 to this ethylenically unsaturated carboxylic acid or carboxylic acid anhydride.
It is used in an amount of 1.5 to 1.5 times the mole, preferably 1.1 to 1.4 times the mole.

The adhesive resin used in the present invention is more preferably an ethylene component-vinyl acetate component-ethylenically unsaturated carboxylic acid so as to satisfy the following formulas (1) to (V).

This is an adhesive resin composition containing a copolymer (X) consisting of a phosphoric acid or carboxylic acid anhydride component and a styrene vinyl compound component, and a copolymer (Y) consisting of an ethylene component and a vinyl acetate component.

l VX-Vy I ≦0.20 ・
(r)0.15≦l Vx −Wx +Vy −Wy
l≦0.40-(n)0.01≦Cx-Wx≦1.
5 - (III) 1.0≦n・Sx/Cx≦
2.0 ・(IV)0.1≦Wx/w
y≦10,,,(”/)where vX;
Vinyl acetate component content (weight fraction) v of copolymer (X)
y: Vinyl acetate component content (weight fraction) of copolymer (Y) Cx; Ethylenically unsaturated carboxylic acid or carboxylic acid anhydride component content of copolymer (X) Cmeq/11)S
X: Styrenic vinyl compound component content of copolymer (X) (m-mole/, p) Wx: Blending amount (weight fraction) of copolymer (X) Wy: Blending of copolymer (Y) Amount (weight fraction) n: Number of carboxyl groups contained in one molecule of ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride n-8 When X/CX is less than 1.0, moldability is relatively poor. This also tends to reduce the adhesion to polycarbonate.

On the other hand, when n-8X/Cx exceeds 260, the copolymer (X
) itself becomes cloudy, affecting even the outer layer of the laminate, which is not suitable.

As a particularly preferred example, when maleic anhydride and styrene are used, these compounds are considered to be graft copolymerized to the copolymer (X) in the form of mutual copolymerization. Furthermore, it is considered that styrene used in excess with respect to maleic anhydride is grafted onto the copolymer (X) alone.

Although it is not necessarily clear why an adhesive resin composition that satisfies the above considerations (1) to (V) is preferable, it is important to note the presence or absence of an ethylenically unsaturated carboxylic acid or carboxylic acid anhydride component, and 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 compatibility between p, (X) and (Y), and when the two are blended or coextruded, microphases may occur in the adhesive resin. Separation occurs, which causes a separation between the polycarbonate and the ethylene-vinyl acetate copolymer saponified resin.
It is thought that a good affinity is created and good adhesion and moldability are exhibited for both.

Next, in the present invention, the resin used as layer (A) is a saponified ethylene-vinyl acetate copolymer having an ethylene component content of 20 to 55 mol % and a saponification degree of 90 mol % or more. If the content of the ethylene component is less than 20 moles, melt molding of the obtained 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 molar or more. If it is less than 90 molty, the gas barrier properties will not be low, and various physical properties such as heat resistance and water resistance will also tend to deteriorate, which is not desirable.

The polycarbonate used as layer (B) has diol components linearly bonded via carbonate bonds within the molecule. As the diol component, 4,4'-dihydroxydiphenyl-1,1-ethane, 4,4'-dihydroxydiphenyl-2,2-propane, 4,4'-dihydroxydiphenylsulfo/, etc. are used. These can be obtained by known methods such as transesterifying a carbonate ester such as diphenyl carbonate with or without a catalyst and then subjecting it to reduced pressure, or reacting it with phosgene in the presence of an acid binder. It will be done.

The laminate of the present invention can be obtained by a known method such as extrusion molding, injection molding, or blow molding using a T-die, ring die, etc. using the above-mentioned resin, and secondary molding can also be performed using vacuum or compressed air. . In this case, the polycarbonate (B) # may be placed on the inner layer or may be placed on the outer layer. In addition, as a laminate (A) - (C) - (B)
, (B) -(C)-(A) -(C) -(B), (
A) -(C)-(B)-(C)-(A) and the like can have a multilayer structure. Furthermore, the polycarbonate layer (B) may have a multilayer structure if necessary. In addition, other resin layers (for example, polyethylene, polypropylene, ethylene-
A polyolefin layer such as vinyl acetate copolymer or ethylene-ethyl acrylate copolymer) can also be laminated.

There is no particular limit to the thickness of each layer of the laminate obtained in this way, but the thickness of layer (A) is 10 to 400 μm, and the thickness of layer (C) is 5 to 3 μm.
00μ, and the (B) layer preferably has a thickness in the range of 50 to 3000μ.

In addition, the adhesive strength between each layer of the resulting psycholaminated product is sufficient, and it combines the excellent psychodynamic properties of polycarbonate resin with the excellent barrier performance of saponified ethylene-vinyl acetate copolymer, and is suitable for use in food containers (cups). , etc.), which are useful as packaging materials.The present invention will be demonstrated by the following examples, but the present invention is not limited thereto.

Example 1 A graft copolymerization reaction of ethylene/vinyl acetate copolymer was carried out using the following recipe using a 20-type reactor.

Ethylene-vinyl acetate copolymer 1500 g styrene
54y maleic anhydride
39g benzoyl peroxide
6I xyleno 150 Q
#l/First, ethylene-vinyl acetate copolymer and xylene were charged into a reactor and heated at 115°C under a nitrogen atmosphere.
Stirring was continued for hours 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 added to 1 xylene.
00d, inject the 9 solution, and heat at 115-120℃ for 2
The graft copolymerization reaction was continued for an hour.

After the completion of the polymerization reaction, add 5400 ml of methanol while stirring.
rut was injected and the precipitated powdery material was taken out and dried.

m-mo1e/g was contained at 190℃, load 21
The MI measured at 60I was 0.7g in 710 minutes.

The thus obtained polymer
．． A copolymer Y consisting of an ethylene component and a vinyl acetate component containing 2ii% and an MI of 61/10 minutes (X)/
(Y) = 40/60 ratio. This composition has a vinyl acetate component of 340%, a carboxyl group of 16%, and a carboxyl group of 16%.
meq/& s styrene component 0.14 cm-mole
/ Contains p.

This adhesive resin composition was used as the (C) layer resin, and was obtained by saponifying 99.6 moles of the vinyl acetate component of an ethylene-vinyl acetate copolymer with a vinyl acetate content of 67 moles. η) = 1.11 (phenol/water =
A saponified ethylene-vinyl acetate copolymer resin at 30°C in an 85/15 mixed solution was used as the (A) layer resin, and polycarbonate (Mitsubishi Gas Chemical Co., Ltd.'s [Kneepilon E-2000J (trade name) )) was used as the (B) layer resin, and a laminate was obtained in the following manner.

Equipped with an extruder ■ with an internal diameter of 120 mm, an extruder ■ with an internal diameter of 60 fl φ, and an extruder ■ with an internal diameter of 9011 III φ.
A multi-manifold type three-type, five-layer co-extrusion device is used in which the resin layer melted and extruded from extruder ■ is sequentially merged with the resin from extruder ■ and the resin from extruder I. The B) layer resin is supplied to the extruder ■, the (C) layer resin is supplied to the extruder ■, the (A) layer resin is supplied to the extruder ■, and the die temperature is set to 280.
Coextrusion was carried out at 12 m/min at a take-off speed of (B)/
A laminate with five layers of three types (C) / (A) / (C) / (B) and a good appearance was obtained. The thickness of each layer is 10μ for the (A) layer, 70μ for the (B) layer, and 3μ for the (C) layer.
Peel strength between (A) / (B) (T peel, 200M/
minute) was good at 0.9 kLI/crn.

Comparative Example 1 Example 1 was prepared using a 20-e reactor according to the following polymerization recipe.
A graft polymerization reaction was carried out in the same manner.

Ethylene/vinyl acetate copolymer 1500. ii'Maleic anhydride 39! jbenzoyl peroxide 10g xylene
450 Oyt1 Polymerization temperature 12
A graft copolymer containing no styrene component was obtained. This copolymer was coextruded in the same manner as in Example 1. The resulting laminate had a peel strength of 0.6 kg/an, but it had small irregularities throughout and was of poor practical use.

Comparative Example 2 Polymer (X)K obtained in Example 1 and consisting of ethylene component - vinyl acetate component - ethylenically unsaturated carboxylic acid anhydride component - styrene component, polyethylene ("Milann 45")
(manufactured by Mitsui Petrochemical) (Y) to (X) / (Y)-40/6
It was blended so that it was 0. The resulting composition had a vinyl acetate component content of 9.8% by weight and a carboxyl group content of 0.16%.
meq/fi s Styrene component 0.111m
-mole 7g was contained.

The obtained composition was used as the (C) layer resin and coextrusion was carried out in the same manner as in Example 1. The peel strength of the obtained laminate was 0.
．． Comparative Example 3 A vinyl acetate component was added to the polymer obtained in Example 1 consisting of an ethylene component, a vinyl acetate component, an ethylenically unsaturated carboxylic acid anhydride, and a styrene component. Ethylene-vinyl acetate copolymer (Y) containing 19% by weight (X)/(Y) = 2/9
It was blended so that it became 8. The resulting composition contained 19.1% by weight of vinyl acetate component and 0.008% of carboxyl group.
meq/g, styrene component 0,007 m-mo
le/fi gold-bearing teita.

Coextrusion was carried out in the same manner as in Example 1 using the obtained composition as the (C) layer resin. The peel strength of the obtained laminate was 0.11 w/image, which is quite low.

Comparative Example 4 Using exactly the same method as in Example 1 except that the amount of styrene was changed to 75 g, the vinyl acetate content was 24.5% by weight, the carboxyl group was 0.40 meq/, F and the styrene component was 0.72 m - contains mole/g;
A polymer (X) having an Ml of 0.9 J/10 min was obtained, but it was extremely cloudy and could not be used as the (C) layer resin for this purpose.

Example 2 Content of vinyl acetate component: 25% by weight and MI: 2.0g
/10 minutes of ethylene-vinyl acetate copolymer, the content of vinyl acetate component is 33.5% by weight and MI2°O,! The vinyl acetate component was 33]ii%, carboxyl group i 0.42 m
A polymer (X) containing the same mole of styrene component and maleic anhydride component and having an MI of 0.9.p/10 minutes was obtained.

Ethylene-vinyl acetate copolymer (Y) with a vinyl acetate component content of 33.5% by weight (X)/(Y) -50/
50. The obtained composition contained 33.3% by weight of vinyl acetate component and 0.21 meq of carboxyl group.
/ i-containing friend.

This adhesive resin composition was used as the (C) layer resin, and was obtained by saponifying 99.5 mol% of the vinyl acetate component of an ethylene-vinyl acetate copolymer with a vinyl acetate content of 56 mol. [η) = 0.96 (phenol/water =
85/15 mixture, 30°C, de/g'') of ethylene-
Saponified vinyl acetate copolymer resin was used as the (A) layer resin, and polycarbonate (Mitsubishi Chemical Corporation ■ (7) "N0VAR
EX 7030A J (trade name)) is used as the (B) layer resin.

This type is equipped with an extruder 1 with an inner diameter of 95mm, an extruder ■ with an inner diameter of 60mm, and an extruder ■ with an inner diameter of 110flφ, and the resin from the extruder ■ is sequentially merged to form the center layer. Using a feed block type three-layer co-extrusion device,
Extruder 1 extrudes the (A) layer and resin +! P, [1 has (
C) Supply the M resin and the (B) layer resin to the extruder ■,
Co-extrusion was carried out at a die temperature of 280°C and a take-up speed of 13rn/min to produce three parts (A) / (C) / (B).
A clean stack of Wll formation was obtained. The thickness of each layer is (A)
The layer is 35μ, the (B) layer is 200μ, and the (C) layer is 20μ, and the peel strength between (A)/(B) is 1.8kp/Iy.
11, which was good and rare.

Comparative Example 5 Polymer (XNC, ethylene-vinyl acetate with a vinyl acetate component of 45% by weight) having an ethylene component - beer acetate component - ethylenically unsaturated carbo/acid anhydride component - styrene component obtained in Example 2 Copolymer (Y) ((i)/(Y)-
This product contains 42.6% by weight of vinyl acetate component and 0.08% of carboxyl group.
It contained meq/9.

Example 2 This adhesive resin composition was used as the (C) layer resin.
Coextrusion is carried out in the same manner. The obtained laminate had a wavy pattern throughout and was of low commercial value. Moreover, the peel strength was low at Q, lkp/m, which was disappointing.

Patent applicant RiRa Shido Co., Ltd. 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%. saponified ethylene-vinyl acetate copolymer (A) with a saponification degree of 90% or more by mole and a polycarbonate (B)
). (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|≦0.20...(I) 0.15≦V_x・W_y+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; Styrenic vinyl compound component content of 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 contained in one molecule of ethylenically unsaturated carboxylic acid or carboxylic acid anhydride