JPH0587548B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyester elastomer resin hot melt adhesive that has excellent heat-resistant adhesive properties, low-temperature adhesive properties, and also excellent thermal stability when adhering various types of plastics, metals, wood, etc. The present invention relates to a polyester elastomer resin hot melt adhesive that has particularly excellent performance in adhering polyolefins to each other, metals to each other, or polyolefins to metals. Polyolefin has excellent chemical properties, is lightweight,
It has excellent features such as being inexpensive and has been widely used in molded products. However, polyolefins such as polyethylene, polypropylene, and polybutene do not have polar parts in their molecules and are highly crystalline, so
Adhesive properties are extremely poor, and this has been a major difficulty in the simultaneous development of polyolefins in various applications, and there has been a desire for the emergence of an adhesive with excellent adhesive performance for polyolefins. . Hot melt adhesives are solvent-free, instant adhesive,
Due to its economic efficiency and convenience, such as adhesion to a relatively wide range of adherends, it has come to be used in large quantities in recent years, mainly in light adhesive fields such as packaging and bookbinding.
However, there are still many problems when applying hot melt adhesives to the field of semi-structural product assembly. That is, general-purpose hot melt adhesives such as ethylene-vinyl acetate copolymer and polyethylene have a low softening point and therefore have a problem of poor heat resistance. In recent years, polyester resins and polyamide resins with high softening points have been used as adhesives with good heat resistance. It has problems such as rapid solidification after application, short open time, and poor adhesion at low temperatures. For example, in the case of adherends with high thermal conductivity such as metals,
The heat of the heated and melted adhesive is removed by the adherend, causing it to solidify more quickly, resulting in poor wetting to the adherend and a problem in that adhesive strength is not produced. For this reason, it is common practice to preheat such adherends in advance and adhere them while preventing heat from escaping from the adhesion, but this poses problems in terms of economy and work efficiency, and also requires a large amount of work. In some cases, it is impossible to preheat the adherend, and in this case, there is a problem in that hot melt adhesives cannot be used. As a countermeasure to such problems,
Lowering the glass transition point of hot melt adhesives can lower the solidifying temperature of the adhesive and improve adhesion at low temperatures, but in many cases lowering the glass transition point also lowers the softening point of the adhesive. In this case, a problem arises in that the heat resistance after adhesion deteriorates. In addition, hot melt adhesives are heated at, for example, 160°C to 200°C in an applicator during melt application.
Thermal stability is required because they are exposed to extremely high temperatures for long periods of time. If a thermally unstable hot melt adhesive is used, problems such as clogging of the applicator gun due to gelation of the decomposed polymer, uneven application amount due to non-uniformity of melt viscosity, and decreased adhesiveness may occur. . A copolymerized polyetherester elastomer of polyester and polyalkylene glycol such as polytetramethylene glycol has been proposed as an adhesive with excellent low-temperature properties and heat resistance.
This adhesive has the disadvantage of poor thermal stability and a large drop in viscosity due to decomposition during hot melt melting, making it difficult to use as a hot melt adhesive. Therefore, it has excellent adhesion from low to high temperatures, and is particularly good at adhesion to polyolefin, and can be bonded to metal without preheating, and also has excellent thermal stability during hot melt melting. The development of hot melt adhesives was desired. As a result of various intensive studies aimed at providing an adhesive with the above-mentioned excellent performance, the present inventors discovered that a thermoplastic segmented copolymerized polyester elastomer using a specific soft segment was combined with a tackifier resin. The present invention was achieved by discovering that a hot melt adhesive containing a specific amount of the following can achieve the desired purpose. That is, the present invention provides (A) (i) 10 to 60% by weight of short chain ester units consisting of an organic dicarboxylic acid mainly composed of an aromatic dicarboxylic acid or an ester-forming derivative thereof and an alkylene glycol having 2 to 10 carbon atoms; , (ii) a long-chain ester unit consisting of an organic dicarboxylic acid containing an aromatic dicarboxylic acid as a main component or an ester-forming derivative thereof and α,ω-1,2-polybutadiene glycol having an average molecular weight of 350 to 6000 or a hydrogenated product thereof; /or average molecular weight 350~
6000 α,ω-1,2-polybutadiene dicarboxylic acid or its hydrogenated product or its ester-forming derivative and 90 to 40% by weight of long chain ester units consisting of alkylene glycol having 2 to 10 carbon atoms, and Viscosity 0.5 to 1.5 [in a mixed solvent of phenol:tetrachloroethane=1:1 (weight ratio),
Measured at 20℃. Same below. ] thermoplastic segmented copolymerized polyester elastomer 30-90% by weight
and (B) a hot melt adhesive comprising 70 to 10% by weight of a tackifier resin that is miscible with the polyester elastomer. The thermoplastic segmented copolymerized polyester elastomer in the present invention is composed of a hard segment consisting of short-chain ester units and a soft segment consisting of long-chain ester units. The hard segment raises the softening point of the adhesive and contributes to imparting heat resistance, while the soft segment lowers the glass transition point of the adhesive and maintains excellent adhesion even at low temperatures, especially when preheating metals. By having 1,2-polybutadiene or a hydrogenated substance in the skeleton, which has an affinity for polyolefins, it not only provides excellent adhesion to polyolefins, but also has an affinity for polyolefins. This contributes to facilitating the formulation of tackifiers. The hot melt adhesive of the present invention, which is made of a thermoplastic segmented copolymerized elastomer obtained by copolymerizing these hard segments and soft segments, has the excellent performance of both hard segments and soft segments, and , excellent thermal stability, and other desirable properties. The ratio of short chain ester units to long chain ester units in the thermoplastic segmented copolymerized polyester elastomer is in the range of 10:90 to 60:40, preferably 30:70 to 50:50, by weight. If the proportion of short-chain ester units is less than 10% by weight, the retention of heat resistance will be poor, and the effect of copolymerizing hard segments into segments will be difficult to produce.
If the weight percentage is exceeded, the low-temperature properties will deteriorate, the adhesive will become hard and brittle, and the adhesion at room temperature will also decrease, especially the adhesion to polyolefin will drop rapidly, and it will also be difficult to adhere to metal without preheating. Become. The short chain ester units constituting the hard segments of the segmented copolymer polyester elastomer in the present invention are composed of an organic dicarboxylic acid whose main component is an aromatic dicarboxylic acid or an ester-forming derivative thereof and an alkylene glycol having 2 to 10 carbon atoms. It consists of Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid,
Examples include phthalic acid and naphthalene dicarboxylic acid, and two or more of these can be used, but terephthalic acid or a mixture of terephthalic acid and isophthalic acid is particularly preferably used. Examples of organic dicarboxylic acids include saturated aliphatic dicarboxylic acids having a methylene group of 4 to 20 carbon atoms, such as succinic acid, adipic acid, azelaic acid, sebatenic acid, and dodecanedioic acid, or ester-forming derivatives thereof such as methyl esters. One type or two or more types can be used. In particular, a short organic dicarboxylic acid component consisting of 90 to 50% by weight of an aromatic dicarboxylic acid and 10 to 50% by weight of a saturated aliphatic dicarboxylic acid whose methylene group has 7 to 20 carbon atoms is used. Chain ester units are particularly preferred for the present invention. Examples of the alkylene glycol having 2 to 10 carbon atoms include ethylene glycol, trimethylene glycol, 1,4-butanediol, 1,5
-Alkylene glycols such as pentanediol, 1,6-hexanediol, and neopentyl glycol are mentioned. The long-chain ester unit constituting the soft segment consists of an organic dicarboxylic acid component or glycol component constituting the short-chain ester unit, and an elastomer component formed into an ester with the organic dicarboxylic acid component or glycol component. As an elastomer component, about 350 to 6000, preferably about
α, ω-1,2 with average molecular weight between 600 and 4000
- Polybutadiene glycol or its hydrogenated product, or α,ω-1,2-polybutadiene dicarboxylic acid or its hydrogenated product or its ester-forming derivative having an average molecular weight of about 350 to 6000, preferably about 600 to 4000. is used. In the present invention, such 1,
By using the 2-polybutadiene component, it is possible to obtain a hot melt adhesive having particularly excellent adhesive properties and thermal stability. The thermoplastic segmented copolymerized polyester elastomer in the present invention has an intrinsic viscosity of 0.5 to 1.5.
It is within the range of . If the intrinsic viscosity is less than 0.5, the adhesive strength tends to decrease, while if it exceeds 1.5, the melt viscosity becomes too high and is unsuitable for use. The method for producing the thermoplastic segmented copolyester elastomer in the present invention is not particularly limited, and can be carried out in accordance with known ordinary methods. For example, the organic dicarboxylic acid component, alkylene glycol component, α, ω-1,
It is possible to adopt a method in which the 2-polybutadiene glycol component and/or the α,ω-1,2-polybutadiene dicarboxylic acid component are directly esterified simultaneously or in stages, or they are subjected to transesterification reaction and then polymerized. In addition, high molecular weight or low molecular weight copolyester and α, ω-1,
It is also possible to adopt a method in which the 2-polybutadiene glycol component and/or the α,ω-1,2-polybutadiene dicarboxylic acid component are subjected to transesterification reaction, and then polymerization is carried out in some cases. Any known catalysts, stabilizers, modifiers or additives may be used during these polymerization or transesterification reactions. The hot melt adhesive of the present invention is obtained by blending the thermoplastic segmented copolymerized polyester elastomer and a tackifier resin that is miscible with the polyester elastomer. The blending ratio of both components is 30 to 90% by weight of the thermoplastic segmented copolyester elastomer and 70 to 10% by weight of the tackifier resin. If the amount of the tackifier resin blended is less than 10% by weight, the effect of the blending will not be recognized, while if it exceeds 70% by weight, the plasticizing effect will become large and the cohesive force or heat resistance of the adhesive will decrease. Examples of the tackifier resin include hydrogenated rosin,
Rosin derivatives such as esterified rosin and polymerized rosin, terpene resins such as terpene and terpenephenol copolymers, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, and polymers of unsaturated hydrocarbons (olefin type, diolefin type) , isoprene resin, hydrogenated hydrocarbon resin, polybutene, liquefied polybutadiene, petroleum-based hydrocarbon resin such as low molecular weight butyl rubber, or coumaron indene resin,
Examples include styrene resins, but petroleum hydrocarbon resins having a molecular weight of about 500 to 3,000 are particularly preferred, as they are highly compatible with the elastomer component of the polyester elastomer. The hot melt adhesive of the present invention can be applied in a molten state onto an adherend using a general hot melt applicator or roll coater, or can be used in the form of powder, chips, tape, etc.
It is also possible to form the adhesive into various forms such as a string, film, or wave, and then sandwich it between adherends, and then heat the adhesive at a temperature higher than the softening point of the adhesive to fuse the adherend. The present invention will be explained in more detail below using Examples. Note that the characteristic values in the examples were measured by the following method. (1) Softening point (°C) Measured by the ring and ball method according to JIS JAI-7. (2) T-type peel strength (Kg/25 mm) Measured at a peel rate of 50 mm/min according to JIS K-6854. (3) Shear creep softening temperature (°C) A load of 450 kg was applied in the shear direction to a test piece bonded with an adhesive area of 2.5 cm x 2.5 cm.
The temperature was raised at a rate of .degree. C./5 minutes, and the temperature when the weight fell was measured. (4) Thermal stability The thermal stability of the adhesive was determined using a Burckfield viscometer (manufactured by Burckfield).
The rate of decrease in melt viscosity was measured when the sample was left at 180°C for 24 hours. Furthermore, "parts" in the examples mean "parts by weight." Examples 1-5, Comparative Examples 1-3 83 mol of dimethyl terephthalate, HOOC
(CH ₂ ) ₁₈ COOH 17 mol, 1,4-butanediol
160 mol and tetrabutyl titanate as catalyst
Polycondensation was carried out using 0.003 mol, and a copolymerized polyester having a melting point of 176°C (measured by differential thermal analysis) was obtained. 60 parts of this copolymerized polyester and an average molecular weight of approx.
Hydrogenated product of α,ω-1,2-polybutadiene glycol of 2000 (manufactured by Nippon Soda Co., Ltd., Nisso-PB GI-
2000) was taken and transesterified in the presence of a tetrabutyl titanate catalyst at 270°C for 2 hours in a nitrogen atmosphere, resulting in a composition of 56% by weight of short-chain ester units and 44% by weight of long-chain ester units. A segmented copolymerized polyester elastomer having a viscosity of 0.78 was prepared (Example 1). Similarly, copolymerized polyester and α, ω-
The blending ratio of hydrogenated 1,2 polybutane diene glycol was 85/15, 70/30, 50/50, 45/ respectively.
55, 37/63, 25/75, 15/85, and the composition ratios of short chain ester units and long chain ester units are respectively 84/16 (Comparative Example 1) and 67/13 (Comparative Example 2). ), 45/55 (Example 2), 40/60 (Example 3),
30/70 (Example 4), 15/85 (Example 5), 5/95
A polyester elastomer (Comparative Example 3) was produced by the above method. To 40 parts of each polyester elastomer, 20 parts of Foral-85 (a rosin derivative with a softening point of 85°C, manufactured by Hercules) and 20 parts of Escorez 5380 (hydrogenated alicyclic petroleum hydrocarbon resin) were added as tackifier resins. 20 parts of Idemitsu Polybutene 300H (hydrogenated polybutene of petroleum oil-based hydrocarbon resin, molecular weight 1330, manufactured by Idemitsu) and Piccolastic
A-50 (low molecular weight styrene homopolymer with softening point
50℃, 10 parts (manufactured by Hercules), 60 parts in total, and Irganox 1010 as an antioxidant.
1 part of [tetrakis [methylene-3-(3',5'-di-tarsially-butyl-4'-hydroxyphenyl)propionate] methane antioxidant, manufactured by Civer Geigy) was mixed at 170°C in a molten state;
Got the glue. The softening point of each adhesive is
Shown in the table. This adhesive was melted at 190℃ and 0.5mm thick.
Apply to an unpreheated aluminum plate with a thickness of 5
After a few seconds, a 2mm thick polypropylene plate was placed on top of the 0.5
Pressure bonding was carried out at Kg/cm ² . Table 1 shows the results of measuring the T-peel strength and shear creep softening temperature of the obtained adhesive sample.

【table】

[Table] However, the adhesives of Comparative Examples 1 and 2 had poor adhesion to aluminum plates without preheating, so
Adhesion was measured by preheating aluminum plates at 190°C and then adhering them. As is clear from comparing Examples and Comparative Examples, when the amount of short chain ester units exceeds 60% by weight, it becomes difficult to adhere to metal without preheating.
In addition, even when preheated and bonded, the adhesion to polyolefin was poor, and the amount was 10% by weight.
When the amount is less than that, adhesiveness and heat resistance are significantly reduced. However, as in the present invention, short chain ester units
Adhesives using polyester elastomers consisting of 10 to 60% by weight and 90 to 40% by weight of long-chain ester units can bond to metals without preheating, and also have excellent adhesion performance to polyolefins. , and has excellent heat resistance. Examples 6 to 8, Comparative Examples 4 to 5 Compared to the polyester elastomer used in Example 3, Fural-8520 used in Examples 1 to 5
Part, Escorets 5380 20 parts, Idemitsu Polybutene
A tackifier resin containing 10 parts of 300H and 10 parts of Picolas Stick A-50 was blended in the proportions shown in Table 2, and 1010 parts of Irganox was added to prepare an adhesive. An adhesion test was conducted in the same manner as in Example 1 using these adhesives. The results are shown in Table 2.

[Table] As is clear from comparing Examples and Comparative Examples, when the blending ratio of tackifier resin is less than 10% by weight, the adhesion to polyolefin deteriorates;
If it exceeds 70% by weight, the adhesive cohesive force will be low, and the adhesive strength and heat resistance (shear creep softening point) will be poor. However, the adhesive of the present invention has excellent adhesion to polyolefin or metal, and also has excellent heat resistance. Example 9 70 mol of dimethyl terephthalate, 30 mol of azelaic acid
mol, 160 mol of 1,4-butanediol and 20 mol of hydrogenated α,ω-1,2-polybutadiene glycol having an average molecular weight of about 2000 were taken, and polycondensation was carried out using 0.003 mol of tetrabutyl titanate as a catalyst. A segmented copolymer polyester elastomer consisting of 30% by weight of short-chain ester units and 70% by weight of long-chain ester units, having a softening point of 166°C (by the ring and ball method) and an intrinsic viscosity of 0.68 was prepared. Escorez 3102 as a tackifier resin was added to 40 parts of this polyester elastomer.
(Aromatic hydrocarbon resin made from petroleum-based hydrocarbon resin, softening point 100℃, manufactured by Etsuso) 20 parts, Piccovar resin L-30 (Aromatic hydrocarbon resin made from petroleum-based hydrocarbon resin, softening point 100℃, 20 parts of Piccoumaronresin 110 (manufactured by Hercules), 10 parts of Piccoumaron Resin 110 (manufactured by Hercules), and 10 parts of Piccolast A-50, a total of 60 parts, and 10101 parts of Irganox as an antioxidant. Mix at 180℃ in molten state,
Created adhesive. Melt this adhesive at 190℃ and apply it to a polyvinyl chloride film with a thickness of 0.35mm, and apply it for 10 seconds each.
After being left for 1 minute and 5 minutes, a 0.5 mm thick aluminum plate that had not been preheated was adhered. When the 180° peel strength of the obtained adhesive sample was measured at a tensile speed of 200 mm/min, it was 8.5 Kg/25 mm, respectively.
It was 7.2Kg/25mm and 7.5Kg/25mm. In addition, the shear creep softening temperature was 115°C. moreover,
The thermal stability of this adhesive was 4% in terms of the rate of decrease in melt viscosity after being left at 180° C. for 24 hours. Example 10 α,ω- with an average molecular weight of about 2000 instead of the hydrogenated product of α,ω-1,2-polybutadiene glycol
1,2-Polybutadiene glycol (Nippon Soda
30% by weight of short chain ester units, except that Nisso-PB G-2000) was used.
Consisting of long chain ester unit weight%, softening point 161℃
(By the ring and ball method), a segmented copolymerized polyester elastomer with an intrinsic viscosity of 0.65 was obtained. 60 parts of the tackifier resin used in Example 9 and 1 part of the antioxidant were mixed in a molten state with 40 parts of this polyester elastomer to prepare an adhesive. Using this adhesive, a pre-vinyl chloride film and an aluminum plate were bonded together with an open time of 10 seconds in the same manner as in Example 9, and the peel strength was measured at 180°C and found to be 8.9 kg/25 mm. In addition, the shear creep softening temperature was 112°C. Furthermore, the thermal stability of this adhesive was 10% in terms of viscosity reduction. Comparative Example 6 Polytetramethylene glycol with an average molecular weight of about 2000 (Sanyo Kasei Co., Ltd., PTMG2000) was used instead of α,ω-1,2-polybutadiene glycol hydrogenated product.
30% by weight of short chain ester units, 70% by weight of long chain ester units,
A segmented copolymer polyester elastomer with a softening point of 155°C and an intrinsic viscosity of 0.68 was obtained. Example 9 To 40 parts of this polyester elastomer
An adhesive was prepared by mixing 60 parts of the tackifier resin used in 1 and 1010 parts of Irganox in a molten state at 180°C. Using this adhesive, a polyvinyl chloride film and an aluminum plate were bonded together with an open time of 10 seconds in the same manner as in Example 9, and the peel strength at 180°C was measured to be 6.5 kg/25 mm. In addition, the shear creep softening temperature was 107°C. However, the thermal stability of this adhesive was 38% in terms of viscosity reduction rate. As is clear from comparing Examples 9 and 10 and Comparative Example 6, when polytetramethylene glycol is used for the soft segment, the adhesive performance and heat resistance show reasonable values, but the thermal stability is inferior. It has drawbacks and is difficult to use as a hot melt adhesive. However, as in the present invention, α, ω
When -1,2-polybutane diene glycol or its hydrogenated product was used, an adhesive with excellent adhesive performance, heat resistance, and thermal stability was obtained.

Claims (1)

[Scope of Claims] 1 (A) (i) 10 to 60 short chain ester units by weight consisting of an organic dicarboxylic acid whose main component is an aromatic dicarboxylic acid or an ester-forming derivative thereof and an alkylene glycol having 2 to 10 carbon atoms; % and (ii) an organic dicarboxylic acid whose main component is an aromatic dicarboxylic acid or its ester-forming derivative and an average molecular weight of 350~
6,000 α,ω-1,2-polybutadiene glycol or its hydrogenated product and/or α,ω-1, with an average molecular weight of 350 to 6,000.
It consists of 2-polybutadienedicarboxylic acid or its hydrogenated product or its ester-forming derivative and 90 to 40% by weight of long chain ester units consisting of alkylene glycol having 2 to 10 carbon atoms, and has an intrinsic viscosity [phenol:tetrachloroethane= Measured at 20°C in a 1:1 (weight ratio) mixed solvent. A hot melt adhesive comprising 30 to 90% by weight of a 0.5 to 1.5 thermoplastic segmented copolyester elastomer and (B) 70 to 10% by weight of a tackifier resin that is miscible with the polyester elastomer. 2. A patent in which an organic dicarboxylic acid whose main component is an aromatic dicarboxylic acid is composed of 90 to 50% by weight of an aromatic dicarboxylic acid and 10 to 50% by weight of a saturated aliphatic dicarboxylic acid whose methylene group has 7 to 20 carbon atoms. A hot melt adhesive according to claim 1. 3. The hot melt adhesive according to claim 1, wherein the tackifier resin is a resin whose main component is a petroleum-based hydrocarbon resin having an average molecular weight of 500 to 3,000.