JPH03118152A - Polyester resin laminated film - Google Patents

Abstract

PURPOSE:To impart toughness in the release of a seal part after thermal adhesion and to prevent the generation of blocking at the time of rolling-up and at the time of bag making by forming a thermal adhesive layer from two kinds of polyester resins higher and lower than a specific value in the thermal motion start temp. of a molecule measured by a dynamic viscoelasticity measuring apparatus and specifying said temp. of the thermal adhesive layer. CONSTITUTION:In a polyester resin laminated film having a thermal adhesive layer composed of a polyester resin mixture laminated to at least the single surface thereof, the thermal adhesive layer consists of a polyester resin (A) higher than 50 deg.C in the thermal motion start temp. of a molecule measured by a dynamic viscoelasticity measuring apparatus and a polyester resin (B) equal to or lower than 50 deg.C and said temp. of the thermal adhesive layer is 45-60 deg.C. Among polyesters copolymerized by the combination of dicarboxylic acid and diol, the polyester resin (A) is higher than 50 deg.C in temp. largely changing storage elastic modulus, that is, the thermal motion start temp. T of a molecule.

Description

DETAILED DESCRIPTION OF THE INVENTION (Fields of Application in Industries 1 and 6) The present invention relates to a laminated polyester film which is a polyester film with excellent thermal adhesive properties and is used for general packaging purposes and industrial purposes.

(Prior art) Polyester films have excellent mechanical, electrical, chemical, and thermal properties, and are used for packaging,
It is used for various purposes such as electricity, magnetic recording, decoration, and other industrial goods.

However, when using polyester film alone,
Because of its high melting point, it is difficult to thermally bond, so especially for packaging applications, an iIf that imparts thermal adhesiveness is required. Also,
As a stand-alone film, it is used by bonding it with other films to compensate for its undesirable properties.In this case, an adhesive suitable for the purpose is required.On the other hand, the adhesive layer Coating, coextrusion, extrusion lamination, and normal lamination are used as lamination methods using polyester polymers.It goes without saying that when the film is polyester-based, polyester-based adhesives are preferable in terms of interlayer adhesion. However, conventional polyester thermal adhesive layers are often brittle for boat fishing, lack toughness in sealing properties after thermal bonding, and may be difficult to peel off, or the film itself may tear in undesirable directions. In order to solve this problem, attempts have been made to make the thermal adhesive layer softer, but when the film is wound into a roll, the thermal adhesive layer and its inner side If the base material layer that is in contact with the bag sticks, or if the bag is made with the thermal adhesive layer on the inside, the thermal adhesive layer and the bag will stick together and become difficult to separate, which is what is called blocking. There were many shortcomings.

(Problems to be solved by the invention) The present invention solves the conventional problems described below.
The purpose is to provide a polyester laminated film that provides toughness when peeling off the sealed portion after thermal adhesion and prevents blocking during roll winding and bag making. be.

(Means for Solving the Problems) The polyester resin laminate film of the present invention is a polyester resin laminate film on which a thermal adhesive layer made of a polyester resin mixture is laminated on at least one side.
The thermal adhesive layer is made of a polyester resin (A) whose thermal movement initiation temperature of molecules measured by a dynamic viscoelasticity measuring device is higher than 50°C, and a polyester resin (B) whose temperature is 50°C or lower. This is achieved by keeping the temperature between 45 and 60°C.

The base polyester film in the present invention refers to polyester polymers such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene-1,2-diphenoxy-4,4-dicarboxylate, and other constituent components thereof. It includes any of unstretched, -axially stretched, and biaxially stretched copolymers obtained from such a copolymer. In addition, these films contain antistatic agents, lubricants, antifogging agents, plasticizers, stabilizers,
It may also contain additives such as anti-blocking agents and colorants.

The polyester polymer of the adhesive layer needs to have both tough adhesion and blocking resistance.

In order to realize an adhesive layer having such characteristics, it is necessary to use a mixture of polyester resin (A) and polyester resin (B) copolymerized using the following dicarboxylic acid and diol components.

The dicarboxylic acids used include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and 2,6 naphthalene dicarboxylic acid. Adipic acid, azelaic acid, sebacic acid, pimelic acid, speric acid, undecanoic acid, dodecanedicarboxylic acid, puranric acid, tetradecanedicarboxylic acid, tabucic acid, nonadecanedicarboxylic acid,
There are saturated or unsaturated aliphatic carboxylic acids having a carbon number of 2 to 30, such as tocosandicarboxylic acid, and alicyclic carboxylic acids, such as cyclohexanedicarboxylic acid. Diols used include ethylene glycol, diethylene glycol, butanediol, hexanediol, neopentyl glycol, 2-methyl-2-ethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propane. Diol, 2-methyl-isopropyl-1,3-propanediol, 2-methyl-2-n-hexyl-1,3
-Propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-isopropyl-1,3-propanediol, 2-ethyl-n-hephthyl-1,3-
Propanediol, 2-ethyl-n-hexyl-1,3
-propanediol, 2,2-di-n-propyl-1,
3-propanediol, 2-n-propyl-2-n-butyl-1゜3-propanediol, 2-n-propyl-
2-〇-hebutyl-1,3-propanediol, 2-n
-Propyl-2-n-hexyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, 2-n-butyl-2-〇-hexyl-1,3- Propanediol, 2-n-butyl-2-n-hebutyl-
1,3-propanediol, 2,2-di-n-hebutyl-1,3-propanediol, 2-n-hebutyl-2-
Aliphatic diols such as n-hexyl-1,3-propanediol and 2,2-di-n-hexyl-1,3-propanediol. ■, 4-cyclohexane dimetatool, 1
, 3-cyclohexane dimetatool and other alicyclic diols. There are xylene glycol, ethylene oxide adducts of bisphenol compounds, and aromatic diols.

” By the combination of dicarboxylic acid and diol mentioned above,
Among the copolymerized polyesters, polyester resin (A refers to the temperature at which the storage elastic modulus changes significantly when the temperature dependence of the storage elastic modulus is determined to be 7!11 using a dynamic viscoelasticity measurement device, i.e. Temperature at which the thermal movement of molecules starts; T is 50
Means higher than ℃. The temperature at which the molecules of the polyester (A) start thermal movement; T is preferably 50°C to 80°C.

If T>80°C, the temperature during sealing becomes high, which is not preferable. Polyester (B) is the temperature at which the storage elastic modulus changes significantly when the temperature dependence of the storage elastic modulus is measured using a dynamic viscoelasticity measurement device, that is, the temperature at which the thermal movement of molecules starts; T is 50°C or higher. means. Temperature at which the molecules of the polyester (B) start thermal movement; T is -20°C to 50°C
°C is preferred. When T<-20°C, blocking occurs even when mixed resins are used, which is not preferable. Further, in the case of a laminated film forming method using coextrusion, the variation in film thickness increases, which is not preferable.

Polyester (A) and polyester (B) are mixed, and the thermal movement initiation temperature of the molecules of the mixture; T' is set to 45 to 60°C.
Mix so that If T'>60°C, the toughness during peeling will be lacking, which is not preferable. Also, T'<45
℃, it lacks blocking resistance and is not preferred.

In the present invention, the polyester serving as the base and the polyesters (A) and (B) constituting the adhesive layer are conventionally used.
- Can be manufactured using the polyester manufacturing method used in membranes. Examples include a direct esterification method in which a dicarboxylic acid and a glycol component are directly reacted, and a transesterification method in which a dialkyl ester of a dicarboxylic acid and a glycol are reacted. Moreover, it does not matter whether it is produced by a batch method or a continuous method. Furthermore, those produced by blending copolymerized polyesters other than those mentioned above may also be used. In addition, lubricants such as fine particles of silica and kaolin, derivatives of higher aliphatic acids, etc. may be added as necessary, and further antistatic agents, anti-aging agents, etc.
・Additional agents, ultraviolet inhibitors, coloring agents, etc. may be added. Polyester (A) and polyester (B) according to the invention
) can be mixed using the methods shown below, but are not limited to these methods.

(1) The polyester (A) and the polyester (B) are mixed in the form of a medium and dissolved in a solvent, such as in the form of resin chips, which are dissolved in a solvent after mixing. (2) The polyesters (A) and (B) are melt-mixed using a melt extruder, and the resulting strand or sheet is crushed to produce chips. (
, '3) After melting and mixing either polyester (A) or polyester (B) with the combined resin in a polymerization pot containing the other molten resin, chips are made in the same manner as in (2). The lamination method of the thermal adhesive layer and the base material layer includes coextrusion method, extrusion ramie method,
Extrusion coating method, coating method, etc. are used.

(Example) The contents of the present invention are shown in Examples. The method used is shown below.

(1) Molecular thermal motion onset temperature dynamic viscoelasticity measuring device [RHEOROG1' CO, LT
Measurement is performed using D-manufactured, V, ERIIEO5PECTOLERI, and the tensile deformation frequency is 110 Hz. With the obtained temperature-storage modulus curve ↑-, the storage modulus or I
The temperature at which the temperature becomes 10 dyn/crit is defined as the temperature at which the thermal movement of molecules starts: T.

■ Seal energy (represents the toughness of the sealed part) The heat-bonded film (heat-sealed length 10-W) was heated by combining the two heat-adhesive layers into a short Jllt shape at a temperature of 20℃ and a humidity of 65℃. % in the atmosphere
After being left for 4 hours, it was peeled off in one direction at a rate of 2001/min using Tensilon manufactured by Toyo Baldwin, and the area on the chart was taken as the sealing energy (g-am/15 mm).

(3) Blocking-resistant thermal adhesive layer The same as above were laminated and pressed together under the conditions of temperature 50°C, humidity 50%, pressure 0.07 kg weight/Ca 1 hour 24 hr-, and the result was determined as no tackiness... ◎: Almost no tackiness...Δ: Slightly tacky...X:

The abbreviations described in the examples indicate the following substances. TPA; terephthalic acid, IPA; isophthalic acid, SA; sebacic acid, AA; adipic acid, EG; ethylene glycol, Bl
); butanediol, NPG; neopentyl glycol, DEG; diethylene glycol.

Example 1 Two extruders (A, B) connected to one T-type [1 gold
) was prepared. For A, polyethylene terephthalate (intrinsic viscosity 0.62) was heated at 280°C, and for B, Table 1
A blend of the two types of polyesters (A) and (B) shown in Figure 1 is melt-extruded at 280°C, the melt is collected in a T-type "1 gold plate, and the discharged laminated sheet is rotated by a cooling roll (
The mixture was wound around a temperature of 20°C and cooled and solidified. The thickness of this sheet was 200 microns. The polyethylene terephthalate layer was 150 microns and the copolymer layer was 50 microns. This sheet was heated to 90°C and passed between two sets of nip rolls with different rotational speeds in the direction of sheet travel.
．． It was stretched 3 times. This -axially stretched film was sent to a stenter one-type horizontal stretching machine, and while heated to 100°C,
It was doubled.

Next, while loosening this film slightly,
It was treated with hot air at ℃ and rolled up. This film has extremely unique characteristics as a polyester film.
As shown in Table 1, it has high sealing energy,
Excellent blocking resistance.

Examples 2 to 3 A laminated film was obtained in the same manner as in Example 1 except that the mixing ratio of polyester (A) and polyester (B) was changed. The evaluation results of the film are shown in Table-1.

Example 4 A laminated film was obtained in the same manner as in Example 1 except that polyester (A) having a different composition was used. The evaluation results of the film are shown in Table-1.

Example 5 A laminated film was obtained in the same manner as in Example 1 except that a polyester (B) having a different composition was used in Example 1. The evaluation results of the film are shown in Table-1.

Comparative Example 1 In Example 1, a laminated film was obtained using only polyester (A). The evaluation results of the film are shown in Table-1.

Comparative Example 2 In Example 1, a laminated film was obtained using only polyester (B). The evaluation of the film is shown in Table-1.

Comparative Example 3 A laminated film was obtained in the same manner as in Example 1 except that the mixing ratio of polyester (A) and polyester (B) was changed. However, this is different from Examples 1 to 3 in that the temperature at which the molecules of the mixture start thermal movement; T' is higher than 60°C. Table 1 shows the evaluation results of the film.
It was shown to.

Comparative Example 4 A laminated film was obtained in the same manner as in Example 1 except that the mixing ratio of polyester (A) and polyester (B) was changed. However, this example differs from Examples 1 to 3 in that the temperature at which the molecules of the mixture start thermal movement; T' is less than 45°C. Table 1 shows the evaluation results of the film.
It was shown to.

Comparative Example 5 In Example 2, the temperature at which the thermal movement of molecules starts; T is 80°C.
A laminated film was obtained in the same manner as in Example 2 except that a higher polyester (A) was used.

The evaluation results of the film are shown in Table-1.

Comparative Example 6 In Example 2, the temperature at which the thermal movement of molecules starts; T is -20
A laminated film was obtained in the same manner as in Example 2, except that polyester (B) having a temperature of less than .degree. C. was used. The evaluation results of the film are shown in Table-1.

(Effect of the invention) Table 1 shows that when polyesters (A) and (B) are mixed at an appropriate mixing ratio, a film laminate with high sealing energy and excellent blocking resistance can be obtained. It can be seen that under these conditions, sealing energy and blocking resistance are not compatible. Since the polyester film laminated film of the present invention is thus constructed by laminating two specific types of polyester mixtures, the heat-sealed portion has high toughness and also has good blocking resistance. As a result, it is suitable for applications requiring toughness, such as packaging films, and can be widely used.

Claims (1)

[Claims] In a polyester resin laminated film in which a thermal adhesive layer made of a polyester resin mixture is laminated on at least one side, the thermal adhesive layer is a polyester resin whose molecular thermal movement initiation temperature is higher than 50°C as measured by a dynamic viscoelasticity measuring device. A polyester resin laminate film comprising (A) and a polyester resin (B) having a temperature of 50°C or less, and characterized in that the temperature of the thermal adhesive layer is 45 to 60°C.