JPH0157155B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a transparent copolyester adhesive. More specifically, the present invention relates to a copolymerized polyester adhesive which is an adhesive for soft polyvinyl chloride resins (both polyvinyl chloride resins and polyvinyl chloride resins and other adherends), and which has transparency. Aromatic dibasic acid-based saturated polyesters, such as polyethylene terephthalate and polybutylene terephthalate, have excellent mechanical strength, thermal stability, dimensional stability, weather resistance, chemical resistance, etc., and are used as various molding materials and others. Widely used. Various attempts have been made to take advantage of the excellent properties of polyester and apply it to other fields, and adhesives are one such application field. However, polyethylene terephthalate, polybutylene terephthalate themselves, or copolyesters mainly composed of them have high melting points and high crystallinity, so it is extremely difficult to use them as adhesives. Particularly in the field of adhesives, depending on the application, transparency may be required for the adhesive layer itself, and for such purposes, the copolymerized polyester described above, in addition to its high crystallinity, It is difficult to satisfy the expected performance. On the other hand, when adhering soft polyvinyl chloride (vinyl chloride polymers and copolymers) containing plasticizers to themselves or to other adherends, the plasticizers contained (esters such as dioctyl phthalate) are usually used as adhesives. ) Polyurethane-based adhesives (solution type, emulsion type, film type) are currently being used to prevent adhesion failure due to the phenomenon of migration or exudation of adhesives ( Problems remain in this respect. Taking the above circumstances into consideration, the present inventors conducted extensive studies to obtain a polyester adhesive that has excellent transparency, mechanical strength, thermal stability, weather resistance, etc., and has strong adhesive strength to soft polyvinyl chloride. As a result, we have completed the present invention. That is, in the present invention, the acid component as a constituent component of the copolymerized polyester is 40 to 70 mol% of terephthalic acid residues,
Isophthalic acid residue 60-30 mol%, glycol component 1,4-butanediol 40-70 mol%, neopentyl glycol 60-30 mol%, optionally trivalent or higher carboxylic acid based on 100 mol of the above acid component or/and 5 moles or less of a polyol having a valence of 3 or more, and if desired, 6 carbon atoms per 100 moles of the acid component.
~12 aliphatic dicarboxylic acids of 10 moles or less or/and other aliphatic glycols having 2 to 12 carbon atoms per 100 moles of the glycol component 10 moles or less, and having a reduced viscosity (ηsp/C) of 0.3 to 0.9dl/g
This is a transparent polyester adhesive for soft polyvinyl chloride resin containing a copolymerized polyester as an active ingredient. In the present invention, if the amount of terephthalic acid residue as an acid component in the constituent components of the copolyester is less than 40 mol%, the polyester will lack cohesive strength and mechanical strength, and if it exceeds 70 mol%, it will cause crystallization. It has too high elasticity, lacks flexibility, and has poor transparency. If the isophthalic acid residue content is less than 30 mol%, transparency will not be lost, and if it exceeds 60 mol%, heat resistance and durability will be poor. On the other hand, if the amount of 1,4-butanediol as a glycol component is less than 40 mol%, the molecular cohesive force will be weak and sufficient adhesive strength will not be obtained, and if it exceeds 70 mol%, transparency will be lost. If the amount of neopentyl glycol is less than 30 mol%, transparency will be lacking, and 60 mol%
If it exceeds this, adhesive strength, heat resistance, and chemical resistance will become poor. Further, the amount of the aliphatic dicarboxylic acid having 6 to 12 carbon atoms and/or the aliphatic glycol having 2 to 12 carbon atoms added as required is 100% of the acid component or glycol component.
If the amount exceeds 10 moles, the mechanical strength and transparency of the polyester will decrease. Furthermore, if the amount of trivalent or higher carboxylic acid and/or trivalent or higher polyol added as desired exceeds 5 moles per 100 moles of the acid component, the resin tends to become hard and the adhesive strength tends to decrease. As an aliphatic dicarboxylic acid having 6 to 12 carbon atoms,
For example, adipic acid, azelaic acid, sebacic acid,
Dodecanedioic acid and the like are used, and examples of the trivalent or higher carboxylic acid include trimellitic acid and pyromellitic acid. Also, as aliphatic glycols having 2 to 12 carbon atoms,
For example, ethylene glycol, propylene glycol, pentanediol, hexanediol, decanediol, dodecanediol, etc. are used.
As the trivalent or higher polyol, for example, trimethylolpropane, glycerin, pentaerythritol, etc. are used. Among the copolymerized polyesters using such raw materials, those particularly useful in the present invention have a reduced viscosity (ηsp/
c) is 0.3 to 0.9 dl/g, preferably 0.4 to 0.8. Here, the reduced viscosity (ηsp/c) is in m-cresol solvent, polymer concentration (c) 0.25g/0.25dl, 40℃
This is the value measured at If the reduced viscosity of the copolymerized polyester used in the present invention is less than 0.3 dl/g, the cohesive force of the molecules is weak, so strong adhesion cannot be achieved, and if it exceeds 0.9 dl/g, the copolymerized polyester will not have a strong adhesive force during heat bonding. Wetness to the adherend is insufficient and adhesive strength is weak. The copolymerized polyester of the present invention is produced by a general method used in the production of other linear polyesters. That is, for example, terephthalic acid or its ester-forming derivatives, isophthalic acid or its ester-forming derivatives, aliphatic dicarboxylic acids or its ester-forming derivatives are directly esterified after adding the glycols and catalyst, or after transesterification. There is also a method of polymerization, in which the glycols are added to polybutylene terephthalate, and after thermal depolymerization, isophthalic acid or its ester-forming derivative and aliphatic dicarboxylic acid or its ester-forming derivative are added together with a catalyst for polymerization. There is also. Examples of such catalysts include oxides, halides, acetates, etc. of metals such as zinc, manganese, and magnesium, as well as para-toluenesulfonic acid, titanate esters, etc., and the amount used thereof is 0.01 to 100% of the total system. 0.5% by weight is preferred. By specifying the acid component and glycol component as described above, the copolymerized polyester of the present invention has the following properties:
It is transparent and exhibits excellent performance as an adhesive for soft polyvinyl chloride resin.
It can be applied using hot melt adhesives, solvent-based adhesives, and other methods. When using it as a hot melt adhesive, a so-called hot melt applicator is used, but in such a case, in addition to the above copolyester, benzoin, dimethyl terephthalate,
Modaflow (manufactured by Monsanto), Acronal 4F
(manufactured by BASF Corporation), plasticizers such as dioctyl phthalate and P-oxybenzoic acid, phosphorus compounds such as triphenyl phosphate, stabilizers such as hindered phenols, calcium carbonate, zinc oxide, oxidized Fillers such as titanium, talc, glass fiber, Aerosil, polyethylene,
By blending resins other than polyester, such as polypropylene, nylon, epoxy resins, petroleum resins, etc., it is possible to improve flow characteristics, adhesive characteristics, and other physical properties during heating and melting. In this way, it is possible to obtain a hot melt adhesive that is suitable for adhering so-called soft polyvinyl chloride (vinyl chloride polymer and copolymer) containing a plasticizer to itself or to other adherends. When used as a solvent-based adhesive, it is dissolved in a solvent such as aromatic hydrocarbons such as tetrahydrofuran, methyl ethyl ketone, cyclohexanone, toluene, and xylene, and then coated with a roll coater.
After being applied by spraying, dipping, or other methods, it goes through a process of drying, melting, and adhesion.
Achieve the intended purpose. In this way, it is possible to obtain a transparent polyester adhesive that is suitable for adhering so-called soft polyvinyl chloride (vinyl chloride polymer and copolymer) containing a plasticizer to itself or to other adhesives. . The present invention will be specifically explained below using Examples. Example 1 Dimethyl terephthalate (DMT), 1,4-
Catalytic amounts of butanediol (BD), neopentyl glycol (NPG), and a known catalyst were added to the reaction vessel, and transesterification was carried out at 140-190°C in a nitrogen stream. After the transesterification reaction was completed, the amount of isophthalic acid (IPA) shown in Table 1 was added, and the esterification reaction was carried out at 190-210℃.Then, the temperature was increased and the pressure was reduced at the same time, and the mixture was heated at 50mmHg and 210-270℃. When the polymerization is carried out and the polymer reaches a predetermined reduced viscosity, the reaction is terminated and the copolymerized polyesters A to I as shown in Table 1 are prepared.
I got it. Note that copolymerized polyesters D to I are comparative examples. After molding the transparent copolyester obtained into a film with a thickness of approximately 100 μm using a conventional method,
Sandwich the film between transparent soft polyvinyl chloride sheets (size 10 cm x 2.5 cm, thickness 0.2 mm),
The adhesive strength of the test piece heat-sealed at 150° C. and 3 kg/cm ² for 2 minutes was measured using a Tensilon T-peel at 23° C. at a speed of 200 mm/min. The results are shown in Table-2. Example 2 Copolymerized polyester C was heated to bath temperature using a hot melt applicator (Model XI manufactured by Nordson).
Melt extrusion onto various adhesives (a) shown in Table 3 at 200℃ and nozzle outlet temperature of 220℃ (area weight: approximately 200g/m ² ),
Transparent soft PVC sheet (thickness 0.2mm)
They were quickly pasted together and cooled under pressure to complete the adhesion. T-peel of each test piece at 23℃ or
Table 3 shows the 180° peel strength. Example 3 Copolymerized polyester A was dissolved in tetrahydrofuran (polyester/tetrahydrofuran = 20
g/100ml), after applying the above polyester solution with a bar coater to a primer-treated stainless steel plate with a thickness of 0.5mm (epoxy primer: XS-10 manufactured by Toagosei Kagaku Kogyo Co., Ltd., cured at 200℃ for 10 minutes, thickness 5μ). , and heated at 80°C for 30 minutes to form a polyester layer with a thickness of about 10μ. After preheating the board to 180℃,
Transparent soft polyvinyl chloride sheets with a thickness of 0.2 mm were bonded together using a rubber roller, and the various performances of the bonded plates were evaluated. Table 4 shows the results.

【table】

[Table] * Base metal fracture

[Table] * Polyvinyl chloride fracture ** Cow skin fracture *** Preheating the iron plate to 100℃

[Table] *Both are broken vinyl chloride

Claims (1)

[Claims] 1 As the constituent components of the copolymerized polyester, the acid component is 40 to 70 mol% of terephthalic acid residue, 60 to 30 mol% of isophthalic acid residue, and the glycol component is 40 to 70 mol% of 1,4-butanediol, 60% of neopentyl glycol. ~30 mol%, optionally 5 mol or less of a trivalent or higher carboxylic acid or/and a trivalent or higher polyol per 100 mol of the acid component, further optionally a carbon number of 6 to 12 per 100 mol of the acid component. 10 moles or less of aliphatic dicarboxylic acid or/and 2 to 12 carbon atoms other than those listed above per 100 moles of the glycol component
A transparent polyester adhesive for soft polyvinyl chloride resin, which contains as an active ingredient a copolyester comprising 10 moles or less of aliphatic glycol and having a reduced viscosity (ηsp/c) of 0.3 to 0.9 dl/g.