JP3010647B2 - Polyester resin laminated film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polyester film excellent in heat adhesion, and relates to a laminated polyester film used for general packaging and industrial applications.

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

However, when a polyester film is used alone, it has a high melting point and is difficult to be thermally bonded. Therefore, it is necessary to impart a separate thermal bonding property especially for packaging applications. Also,
As a stand-alone film, it is used as a method for compensating for insufficient properties, by being bonded to another film. At this time, an adhesive suitable for the application is required. On the other hand, a polyester polymer is used for the adhesive layer, coating, co-extrusion, extrusion ramie, and normal lamination are performed as a lamination method, and when the film is a polyester film, the adhesive of the polyester film is an interlayer adhesive. Needless to say, the conventional polyester-based heat-bonding layer is generally fragile and lacks toughness in the sealing properties after heat bonding, and is difficult to be peeled off, or the film itself is preferable. In order to solve this problem, attempts have been made to soften the thermal adhesive layer.However, when the film is rolled up, the thermal adhesive layer And the base material layer that is in contact with the inside of it, or in the case of a bag made with the thermal adhesive layer inside, the thermal adhesive layer Wear and exfoliated difficult, disadvantage called blocking occurs had many.

(Problems to be Solved by the Invention) The present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to impart toughness in peeling of a seal portion after thermal bonding, and At the time of roll winding, and such that blocking does not occur at the time of bag making,
An object of the present invention is to provide a polyester-based laminated film.

(Means for Solving the Problems) The polyester resin laminated film of the present invention is a polyester resin laminated film in which a thermal adhesive layer made of a polyester resin mixture is laminated on at least one surface, wherein the thermal adhesive layer is a molecule defined as follows. Thermal motion start temperature of
It consists of a polyester resin (A) having a temperature higher than 50 ° C and a polyester resin (B) having a temperature of -20 to 50 ° C. The temperature of the heat bonding layer is 45 to 60 ° C, and the heat bonding layer Seal energy strength of bonded film is 740 ~ 900g ・ c
Achieved by being m / 15mm. Here, the thermal motion initiation temperature of a molecule is a curve from temperature to elastic modulus measured at a frequency of 110 Hz of tensile deformation using a dynamic viscoelasticity measuring device, and the storage elastic modulus is 1 × 10 ¹⁰ dyn / It is the temperature at which the cm ² is reached.

The base polyester film in the present invention is polyethylene terephthalate, polyethylene naphthalate,
Polybutylene terephthalate, polyester-based polymers such as polyethylene-1,2-diphenoxy-4,4-dicarboxylate, and unstretched, uniaxial obtained from such a polymer comprising a copolymer mainly composed of these components Both stretching and biaxial stretching are included. In addition, these films include an antistatic agent, a lubricant, an antifogging agent, a plasticity, a stabilizer,
Additives such as anti-blocking agents and coloring agents may be included.

The polyester polymer of the adhesive layer needs to have both toughness adhesiveness and blocking resistance.

In order to realize an adhesive layer having such properties, a polyester resin (A) and a polyester resin (B) copolymerized using the following dicarboxylic acid and diol components,
Must be used in combination.

Examples of the dicarboxylic acid used include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid and 2,6 naphthalenedicarboxylic acid. Adipic acid, azelaic acid, sebacic acid, pimelic acid, suberic acid, undecanoic acid, dodecanedicarboxylic acid, brassic acid, tetradecanedicarboxylic acid, tabsic acid, nonadecanedicarboxylic acid, carbon number C such as docosandicarboxylic acid; 2 to 30 And alicyclic carboxylic acids such as saturated or unsaturated aliphatic carboxylic acids and cyclohexanedicarboxylic acids. Examples of the diol used include ethylene glycol, diethylene glycol, butanediol, hexanediol, neopentyl glycol, 2-methyl-2-ethyl-1,3-propanediol, and 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-heptyl-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-n-heptyl-1,3-
Propanediol, 2-n-propyl-2-n-hexyl-1,3-propanediol, 2,2-di-n-butyl-1,
3-propanediol, 2-n-butyl-2-n-hexyl-1,3-propanediol, 2-n-butyl-2-
n-heptyl-1,3-propanediol, 2,2-di-n-
Aliphatic diols such as heptyl-1,3-propanediol, 2-n-heptyl-2-n-hexyl-1,3-propanediol, and 2,2-di-n-hexyl-1,3-propanediol . Alicyclic diols such as 1,4-cyclohexanedimethanol and 1,3-cyclohexanedimethanol. There are aromatic diols such as xylene glycol and ethylene oxide adducts of bisphenol compounds. Among the polyesters copolymerized by the combination of the above dicarboxylic acid and diol, the polyester resin (A) refers to the polyester resin (A) that is stored when the temperature dependence of the storage elastic modulus is measured using a dynamic viscoelasticity measuring device. Temperature at which the elastic modulus changes significantly,
That is, a temperature at which thermal motion onset of the molecule; T is higher than 50 ° C. Thermal motion initiation temperature of the polyester (A) molecule; T is preferably from 50C to 80C. When T> 80 ° C., the temperature for sealing increases, which is not preferable. Polyester (B) is a temperature at which the storage elastic modulus changes greatly, that is, the temperature at which the molecule begins to move in a thermal motion; Means things. Thermal motion initiation temperature of the polyester (B) molecule; T needs to be -20 ° C to 50 ° C. When T <−20 ° C., it is not preferable because blocking occurs even when a mixed resin is used. Further, in the case of the multilayer film forming method by co-extrusion, the variation in the film thickness is unfavorably large.

The polyester (A) and the polyester (B) are mixed and mixed so that the thermal motion initiation temperature of the molecules of the mixture; T 'is 45 to 60 ° C. When T ′> 60 ° C., the toughness at the time of peeling is lacking, which is not preferable. If T ′ <45 ° C., the blocking resistance is poor, which is not preferable. In the present invention, the polyester serving as the base and the polyesters (A) and (B) constituting the adhesive layer can be produced by a conventional polyester production method. For example, a direct esterification method in which a dicarboxylic acid is directly reacted with a glycol component, or a transesterification method in which a dialkyl ester of a dicarboxylic acid is reacted with a glycol, and the like are described. It may be manufactured by either a batch method or a continuous method. Further, a copolymer polyester other than those described above may be produced by blending. If necessary, a lubricant composed of fine particles such as silica and kaolin, and a lubricant such as a higher fatty acid derivative may be added.Furthermore, an antistatic agent, an antioxidant, an ultraviolet ray inhibitor and a coloring agent may be added. You may. The method for mixing the polyester (A) and the polyester (B) according to the present invention includes, but is not limited to, the following methods.

(1) Polyester (A) Polyester (B) dissolved alone in a solvent is mixed or dissolved in a solvent after mixing in a resin chip shape or the like. (2) The polyesters (A) and (B) are melt-mixed with a melt extruder, and the strands or sheets are pulverized to produce chips. (3) One of the polyesters (A) and (B) is melt-mixed in a polymerization vessel containing the polymerized resin and the other molten resin, and chips are produced in the same manner as in (2). A coextrusion method, an extrusion ramie method, an extrusion coating method, a coating method, or the like is used as a method of laminating the heat bonding layer and the base material layer.

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

(1) Thermal motion initiation temperature of molecules Dynamic viscoelasticity measurement device [DVERHEOSP manufactured by RHEOROGY CO.LTD
[ECTOLER], and measure at a frequency of 110 Hz of pulling deformation. On the curve from the obtained temperature to the storage elastic modulus, the temperature at the point where the storage elastic modulus becomes 1 × 10 ¹⁰ dyn / cm ² is defined as the thermal motion onset temperature of the molecule; T.

(2) Sealing energy (representing the toughness of the seal) The heat-bonded layers are combined to form a heat-bonded film (heat-seal length 10 mm) into a strip with a width of 15 mm, and a temperature of 20 ° C.
After standing in an atmosphere of 65% humidity for 24 hours, peel off at a speed of 200 mm / min in one direction using Toyo Baldwin's Tensilon, and seal the area on the chart with the sealing energy (gcm / 15m).
m).

(3) Blocking resistance The thermal adhesive layers are stacked on top of each other at a temperature of 50 ° C, a humidity of 50%, and a pressure of 0.
Crimping was performed under the conditions of 07 kg weight / cm ² , time: 24 hours. The result was judged as “no stickiness”: ◎ mark, almost no stickiness… △ mark, fairly sticky… × mark.

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, BD; butanediol,
NPG; neopentyl glycol, DEG; diethylene glycol.

Example 1 Two extruders (A, B) connected to one T-type base
Was prepared. For A, polyethylene terephthalate (intrinsic viscosity 0.62) at 280 ° C., and for B, 28% of a blend of the two polyesters (A) and (B) shown in Table 1 was used.
The melt was extruded at 0 ° C., the melt was collected in a T-type die, and the discharged laminated sheet was wound around a rotating cooling roll (temperature: 20 ° C.) to be 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 stretched 3.3 times in the sheet advancing direction between two sets of nip rolls having different rotation speeds. This uniaxially stretched film is sent to a stenter type transverse stretching machine, and 10
The film was stretched 3.3 times while heating to 0 ° C. Subsequently, the film was treated with hot air at 220 ° C. while being slightly relaxed, and wound up. This film has extremely useful properties as a polyester film, and as shown in Table 1, has high sealing energy and 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 the polyester (A) and the polyester (B) was changed. Table 1 shows the evaluation results of the film.

Example 4 A laminated film was obtained in the same manner as in Example 1 except that another coarse polyester was used as the polyester (A). Table 1 shows the evaluation results of the film.

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. Table 1 shows the evaluation results of the film.

Comparative Example 1 In Example 1, a laminated film was obtained using only the polyester (A). Table 1 shows the evaluation results of the film.

Comparative Example 2 In Example 1, a laminated film was obtained using only the polyester (B). Table 1 shows the evaluation of the film.

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

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

Comparative Example 5 A laminated film was obtained in the same manner as in Example 2, except that the polyester (A) having a molecular thermal onset temperature; T higher than 80 ° C. was used. Table 1 shows the evaluation results of the film.

Comparative Example 6 In Example 2, the thermal motion onset temperature of the molecule; T was −20 ° C.
Example 2 except that the polyester (B) which is less than
A laminated film was obtained in the same manner as described above. Table 1 shows the evaluation results of the film.

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

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (1)

(57) [Claims] 1. A polyester resin film in which a heat-adhesive layer comprising a polyester-resin mixture is laminated on at least one side, wherein the heat-adhesive layer is a polyester resin (A) having a molecular motion onset temperature higher than 50 ° C. as defined below. And-
The temperature of the heat-bonding layer is 45-60 ° C, and the sealing energy strength of the heat-bonded film with the heat-bonding layers together is 20-50 ° C.
A polyester resin laminated film characterized by being 740 to 900 gcm / 15 mm. Here, the thermal motion initiation temperature of a molecule is a curve from temperature to elastic modulus measured at a frequency of 110 Hz of tensile deformation using a dynamic viscoelasticity measuring device, and the storage elastic modulus is 1 × 10 ¹⁰ dyn / cm ²
Is the temperature at which