TW201922839A - Polyester polyols based on phthalic acid having low viscosity - Google Patents

Abstract

The present invention relates to polyester polyols having a low viscosity, a method for the preparation thereof, and the use thereof in an adhesive composition. The present invention also relates to an adhesive composition comprising the described polyester polyol, a polyurethane adhesive which can be obtained by reacting the polyester polyol with an isocyanate component, and a method for bonding using the polyurethane adhesive.

Description

   Polyester polyol with low viscosity based on phthalic acid   

The present invention relates to some polyester polyols with low viscosity, a method for preparing the same and its use in an adhesive composition. The invention also relates to an adhesive composition comprising the aforementioned polyester polyol; a polyurethane adhesive, which can be obtained by reacting the polyester polyol with an isocyanate component; and a method for using the same Method for bonding the polyurethane adhesive.

Many polyester polyols are mainly linear polymers, which are characterized by low production costs and a wide range of applications. For example, many polyester polyols are used to formulate reactive adhesive systems, which can be widely used in the preparation of many products, ranging from simple everyday items such as food packaging to many complex systems.

A polyester polyol that enjoys particular economic success. It is a polyol product that can be obtained by the esterification of phthalic acid or phthalic anhydride with a polyhydric alcohol. For example, such polyol products are usually Presented as some viscous liquids and capable of reacting with many isocyanate compounds to form coatings, adhesives, foams, sealants and elastomers. These have many excellent properties, such as tensile strength, adhesion (adhesion) and abrasion resistance (resistance to abrasion).

One of the problems caused by the use of this polyester polyol is its high viscosity, which usually requires some solvents or other methods of adjusting the desired viscosity to achieve proper operation, especially when pumping and mixing When using compounds, for some ecological and economic reasons, avoid using solvents in large quantities. Other methods of reducing viscosity, such as heating these compounds, are often associated with costly technology and energy, and can only be incorporated into industrial processes with difficulty.

Therefore, some polyester polyols with low viscosity and easy handling are needed.

WO 99/42508 describes a low-viscosity aromatic polyester polyol, which includes an inter-esterification product, from 20 to 80 mol.% Of benzene with diethylene glycol Dicarboxylic acid-based materials, consisting of a higher-functional polyol with an average functionality greater than two, and a long-chain alkyl acid, a long-chain ester or oil.

WO 2001/30878 discloses some polyester ether polyols, which are reaction products from the reaction of phthalic acid with ethylene glycol and propylene oxide.

However, the various proposed solutions described in the prior art have the disadvantage that they are, to a certain extent, very complicated, and the starting materials used require special precautions to operate, because these materials are Health is potentially risky or because it burns easily.

Therefore, the problem to be solved by the present invention is to provide a polyester polyol, which has low viscosity, can be industrially processed, and is used in some adhesive compositions.

Surprisingly, this problem is solved by a polyester polyol, which can be obtained by a simple transesterification reaction of an ester with a polyol, which is based on phthalic acid. The material is formed with at least one polyhydric alcohol, which is described in more detail below.

The present invention is firstly related to a low-viscosity polyester polyol, which is formed by a transesterification reaction of an ester (A) and a polyol (B). The ester (A) The base material is formed by reacting with at least one polyol.

In the concept of the present invention, a polyester polyol refers to a polyol containing some ester bonds.

It has been proven that, especially with regard to polyester polyols used in many adhesive compositions, the polyester polyol must have a viscosity that allows it to be well mixed with the other ingredients of the adhesive composition and be evenly coated It is placed on the substrate to be bonded, and it confirms that there is a good adhesion to the substrate. It has been surprisingly shown that when the viscosity of the polyester polyol is not more than 30,000 mPas at 25 ° C, a good balance of these requirements can be achieved. Therefore, in one embodiment of the present invention, the polyester polyol of the present invention is measured at 25 ° C in each case, and preferably has a viscosity of 1,000 to 30,000 mPas, and more preferably 1,000 to 15,000 mPas.

Ester (A)

According to the present invention, the polyester polyol is obtained by a transesterification reaction of an ester (A) and a polyol (B), and the ester (A) is obtained from a phthalic acid-based material and at least one Composed of polyols.

Preferably, the at least one polyhydric alcohol is selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, glycerol, diglycerol, and glycerol. A group of low molecular weight derivatives. The low molecular weight derivative of glycerol preferably has a molar mass of less than 600 g / Mol, more preferably less than 400 g / Mol. In a particularly preferred embodiment, the at least one polyhydric alcohol is selected from the group consisting of ethylene glycol, propylene glycol and glycerol.

In the context of the present invention, the phthalic acid-based material is understood to mean a material having a functional group of at least one phthalic acid as a structural unit.

In this case, the phthalic acid-based material is particularly selected from the group consisting of phthalic anhydride, phthalic acid, isophthalic acid, terephthalic acid, phthalic acid, isophthalic acid, or terephthalic acid. Methyl ester, dimethyl terephthalate, polyethylene terephthalate, trimellitic acid anhydride, pyromellitic acid anhydride, And their mixtures.

In a particularly preferred embodiment of the present invention, the phthalic acid-based material is phthalic acid or phthalic anhydride. In a particularly preferred embodiment of embodiments, the phthalic acid based material is phthalic Foundations - acid (ortho -phthalic acid). It has surprisingly been shown that many particularly beneficial results can be achieved by using these compounds, especially regarding the viscosity of the product and the yield of the esterification reaction.

The ester (A) is composed of the phthalic acid-based material and the at least one polyhydric alcohol, and is preferably prepared under common reaction conditions well known to those skilled in the art. In a preferred embodiment, it is prepared by reacting the phthalic acid-based material with the at least one polyhydric alcohol in the presence of a catalyst. For example, Tetraisopropyl titanate (T i PT) is a suitable catalyst.

Polyol (B)

According to the present invention, the polyester polyol is obtained by a transesterification reaction of an ester (A) and a polyol (B). There should be no special requirements for the polyol (B) used. Instead, some polyols can be used so that the various properties of the polyester polyols of the present invention can be individually adapted to individual requirements.

The polyol (B) is preferably selected from the group consisting of aliphatic polyols, polyester polyols and polyether polyols, especially polycarbonate polyols. A group consisting of polycaprolactone polyols, polybutadiene polyols, polysulfide polyols, and mixtures thereof.

Suitable polyether polyols include linear and / or branched polyethers, which have several ether bonds and at least dihydroxyl groups, and preferably do not contain any additional functional groups in addition to these hydroxyl groups. Examples of such suitable polyether polyols are polyoxyalkylene polyols, such as polyethylene glycol, polypropylene glycol, polytetramethyl glycol, and Polybutyl glycol. In addition, the aforementioned homopolymers and copolymers of polyoxyalkylene polyols and mixtures thereof can be used. Particularly suitable copolymers of polyoxyalkylene polyols are those including ethylene glycol, propylene glycol, diethylene glycol, propylene glycol, and triethylene glycol. , 2-ethylhexanediol-1,3-glycerol, 2-ethylhexanediol-1,3-glycerol, 1,2,6-hexanetriol, trimethylolpropane (trimethylolpropane), trimethylolethane, tris (hydroxyphenyl) propane, triethanolamine, and triisopropylamine Adduct with at least one compound selected from the group consisting of ethylene oxide, propylene oxide and butylene oxide.

In a particularly preferred embodiment, the polyol (B) is selected from the group consisting of polypropylene glycol, polytetramethyl glycol, ethylene oxide, and propylene oxide. oxide) group of statistical copolymers (statistical copolymers) and / or block copolymers (block copolymers).

In a preferred embodiment, the polyol (B) is a polyester. For example, suitable polyester polyols can be obtained by condensing one or more polyhydric alcohols having 2 to 15 carbon atoms and one or more polycarboxylic acids having 2 to 14 carbon atoms ( polycarboxylic acids). Suitable examples of many polyhydric alcohols include ethylene glycol, glycerin, propylene glycol, such as 1,2-propylene glycol and 1,3-propylene glycol, pentaerythritol , Trimethylolpropane, trimethylolpropane, 1,4,6-octanetriol, butanediol, pentanediol, hexanediol, Dodecanediol, octanediol, chloropentanediol, glycerol monoallylether, glycerol monoethylether, ethylene glycol Alcohol, 2-ethylhexanediol, 1,4-cyclohexanediol, 1,2,6-hexanetriol, 1,3,5-hexanetriol (1,3,5-hexanetriol) and 1,3-bis- (2-hydroxyethoxy) propane (1,3-bis- (2-hydroxyethoxy) propane).

Examples of suitable polycarboxylic acids are phthalic acid, isophthalic acid, terephthalic acid, tetrachloroterephthalic acid, malay Maleic acid, dodecylmaleic acid, octadecenylmaleic acid, fumaric acid, aconic acid, trimellitic acid acid), 3,3'-thiodipropanoic acid, succinic acid, adipic acid, malonic acid, glutaric acid ( glutaric acid), pimelic acid, sebacic acid, cyclohexane-1,2-dicarboxylic acid, 1,4-cyclohexadiene -1,2-dicarboxylic acid (1,4-cyclohexadiene-1,2-dicarboxylic acid), 3-methyl-3,5-cyclohexadiene-1,2-dicarboxylic acid (3-methyl-3 , 5-cyclohexadiene-1,2-dicarboxylic acid) and corresponding acid anhydrides, acid chlorides and acid esters, such as phthalic acid anhydride, phthalic acid chloride ( phthaloyl chloride) and dimethyl ester of phthalic acid.

According to the invention, the polyester polyol is characterized by special properties, along with physical and chemical properties, which also take into account other aspects, such as health risks, and especially with the starting ingredients used.

Occasionally, phthalic acid and its derivatives, especially low molecular weight phthalates, have been suspected of potential health risks and, for example, caused infertility, obesity and Diabetes. Therefore, the use of such compounds, especially in the production of daily goods, should be taken seriously. However, there are no options that can be maintained at a certain level, especially for use in some reactive adhesive compositions, and therefore, it requires such structural units to be present, kept as low as possible, and the adhesion will not be affected in any way. Various properties of the agent system have a negative impact. It has been surprisingly shown that the amount of the phthalic acid or related compounds used in the prior art can be considerably reduced without any reduction in the characteristics of the polyester polyol or subsequent adhesive composition .

Therefore, according to the present invention, in the preferred embodiment of the polyester polyol, the ratio of the phthalic acid residue in the polyester polyol is not more than 30 mol.%. According to the invention, the polyester polyol preferably comprises from 5 to 30 mol.%, Particularly preferably from 7 to 15 mol.% Of a phthalic acid residue. In the polyester polyol of the present invention, the proportion of phthalic acid residues can be maintained. Within certain specific ranges, it can limit contact with these substances that are potentially harmful to health without reducing the polyester polyol nature.

In the sense of the present invention, phthalic acid residue refers to this general group Among them, the aromatic ring may have up to 4 substituents of the structure -COO- and some optional additional substituents.

In a preferred embodiment, according to DIN 53240-2, the polyester polyol of the present invention is characterized in that the number of OH groups in the polyester polyol is 40 to 100 mgKOH / g, preferably 45 to 80 mg KOH / g. Surprisingly, in the polyester polyol, the number of OH groups, in some confirmed ranges, in many adhesive compositions, allows the polyester polyol to be processed particularly well ( processed).

According to the present invention, as determined according to DIN EN ISO 2114, the polyester polyol preferably has an acid value (SZ) of less than 2 mg KOH / g, more preferably less than 1 mg KOH / g. In this way, it is ensured that the polyester polyol has sufficient purity, allowing it to be reliably used in some adhesive compositions.

As mentioned above, the methods described in the prior art are used to prepare some low viscosity polyester polyols based on phthalic acid. The disadvantage of these methods is that many flammable and explosive starting materials, such as many reactions Reactive epoxy compounds (reactive epoxides) are used in their preparation. In order to overcome these disadvantages, the present invention also relates to a method for preparing some low viscosity polyester polyols based on phthalic acid, in which many reactive epoxy compounds can be ignored.

According to the present invention, the method for preparing the polyester polyol is characterized in that in the first step, a material based on phthalic acid is esterified with at least one polyhydric alcohol to obtain an ester (A) Moreover, in the second step, the ester (A) is subjected to a transesterification reaction with the polyol (B), thereby obtaining the polyester polyol. Therefore, the polyester polyol is prepared by transesterification of the ester (A). The ester (A) is composed of a phthalic acid-based material and at least one polyhydric alcohol. The ester is first Prepared in steps. During this reaction, according to the invention, many of the residues introduced in the first step of the method are replaced by the polyol (B), and this includes the separation of at least one of the residues introduced (splitting).

The ester (A) can be prepared by the method described above and uses the above-mentioned phthalic acid-based material. The aforementioned various compounds are preferably used as the polyol (B).

The phthalic acid-based material and the at least one polyhydric alcohol are preferably reacted in a weight ratio of 3: 1 to 0.9: 1, particularly preferably 2: 1 to 1.1: 1. The phthalic acid-based material is particularly preferably added in a slight excess.

The ester (A) obtained in the first step is reacted with the polyol (B) in the second step. The weight ratio of the polyol (B) to the ester (A) is preferably 12: 1 to 2: 1. Particularly preferred is 9: 1 to 3: 1.

In a preferred embodiment, the method of the present invention does not include the use of alkoxylation agents, especially those selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide A group of butylene oxide and mixtures thereof.

The ester (A) composed of a phthalic acid-based material and at least one polyhydric alcohol is preferably transesterified under various common reaction conditions well known to those skilled in the art. In a preferred embodiment, the trans-esterification reaction occurs in the presence of a catalyst. For example, Tetraisopropyl titanate (T i PT) is a suitable catalyst.

The invention also relates to a polyester polyol which can be obtained by the method of the invention.

According to the present invention, the polyester polyol is particularly suitable for use in some adhesive compositions. Therefore, the present invention also relates to an adhesive composition including the low viscosity polyester polyol of the present invention.

In a preferred embodiment, in addition to the polyester polyol of the present invention, the adhesive composition also includes an isocyanate component.

In the concept of the present invention, the isocyanate component is understood to mean various compounds having at least one free isocyanate group (NCO group). The isocyanate component is preferably selected from the group consisting of polyisocyanates and NCO-containing prepolymers.

In the concept of the present invention, the polyisocyanate is various compounds containing at least two reactive NCO groups, preferably diisocyanate or triisocyanate.

Suitable NCO-containing prepolymers are various reaction products of compounds bearing OH and / or NH groups and an excess of polyisocyanate. There are no special requirements for these polymers and the polyisocyanate used, such as The polyisocyanates can be various isocyanates as described above, for example, polyether amines can be used as compounds having an NH group. The above-mentioned various polyols can be used as a compound having an OH group, and then the obtained prepolymer can be further reacted with another or the same polyol.

The isocyanate component is preferably selected from the group consisting of 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 2, 4'-diphenylmethane diisocyanate (2,2'-diphenylmethane diisocyanate), 2,2'-diphenylmethane diisocyanate, hydrogenated or partially hydrogenated MDI (H12MDI, H6MDI), benzene Xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), di- and tetraalkylene diphenylmethyl diisocyanate , 4,4'-dibenzyl diisocyanate, 1,4-phenyldiisocyanate, 1,4-phenyldiisocyanate, 1,4-phenyldiisocyanate (1,4 -phenyl diisocyanate), an isomer of toluene diisocyanate (TDI), 1-methyl-2,4-diisocyanatocyclohexane, 1, 6-diisocyanato-2,2,4-trimethylhexane , 1,6-diisocyanato-2,4,4-trimethylhexane (1,6-diisocyanato-2,4,4-trimethylhexane), 1-isocyanatomethyl-3-iso Cyano-1,5,5-trimethylcyclohexane (1-isocyanatomethyl-3-isocyanato-1,5,5-trimethylcyclohexane (IPDI), chlorinated and brominated diisocyanate, phosphorus-containing diisocyanate , Tetramethoxybutane-1,4-diisocyanate, tetramethoxybutane-1,4-diisocyanate, naphthalene-1,4-diisocyanate (NDI), butane-1 1,4-diisocyanate (butane-1,4-diisocyanate), hexane-1,6-diisocyanate (HDI), dicyclohexylmethane diisocyanate (dicyclohexylmethane diisocyanate), tetramethylene Tetramethylene diisocyanate, hexamethylene diisocyanate, undecamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-three Methyl-hexane-2,3,3-trimethyl-hexamethylene diisocyanate (2,2,4-trimethyl-hexane-2,3,3-trimethyl-hexamethylene diisocyanate), cyclohexane- 1,4-diisocyanate (cyclohexane-1,4-diisocyanate), ethylene diisocyanate (ethylene diisocyanate), methylenetriphenyl triisocyanate (MITE), phthalic acid-bis-isocyanate- Phthalic acid-bis-isocyanato-ethylester, a diisocyanate with a reactive halogen atom, such as 1-chloromethylphenyl-2,4-diisocyanate, 1 -Bromomethyl-phenyl-2,6-diisocyanate (1-bromomethyl-phenyl-2,6-diisocyanate) and 3,3-bis-chloromethyl ether-4,4'-diphenyl diisocyanate ( 3,3-bis-chloromethylether-4,4'-diphenyl diisocyanate). Other diisocyanates that can be used are trimethyl-hexamethylene diisocyanate, 1,4-diisocyanatobutane, 1,12-diisocyanate 1,12-diisocyanatododecane and dimer fatty acid diisocyanate, lysine diisocyanate, 4,4-dicyclohexamethane diisocyanate (4,4- dicyclohexamethane diisocyanate), 1,3-cyclohexane diisocyanate, and 1,4-cyclohexane diisocyanate.

In a particularly preferred embodiment, the isocyanate component is selected from the group consisting of 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 2,2'-diphenylmethane diisocyanate and their oligomers. A group of polymers (oligomers) and polymers.

In another preferred embodiment, in each case, the content of the isocyanate component in the adhesive composition is 5 to 30 wt.%, Preferably 15 to 25 wt.%, Based on the total weight of the composition. .%.

In another preferred embodiment, in the adhesive composition, the molar ratio of the polyester polyol to the isocyanate component is 5: 1 to 1: 1, preferably 3: 1 to 1.5: 1.

According to the present invention, the adhesive composition preferably further includes a catalyst. All compounds known to catalyze the reaction of isocyanates with alcohols can be used as the catalyst. The catalyst is preferably selected from titanates, such as tetrabutyl titanate and tetrapropyl titanate; tin carboxylates, such as dibutyltin dilaurate (dibutyl tin dilaurate (DBTL), dibutyl tin diacetate, tin octoate; tin oxides, such as dibutyl tin oxide, dioctyl tin oxide ); Organoaluminum compounds, such as aluminum trisacetylacetonate, aluminum trisethylacetonate, chelate compounds, such as titantetraacetylacetonate ); Amine compounds, such as triethylene diamine, guanidine, diphenyl guanidine, 2,4,6-tris (dimethylaminomethyl) phenol (2,4 , 6-tris (dimethylaminomethyl) phenol), morpholine, N-methylmorpholine, 2-ethyl-4-methylimidazole, 1,8-diazine bicyclic ring [5.4.0] -7 (1,8-diazabicyclo- (5,4,0) -undecene-7, DBU), 1,4-diazabicyclooctane (DABCO), 1,4-diazabicyclooctane, DABCO [2,2,2] octane (1,4-diazabicyclo [2,2,2] octane), N, N-dimethylpiperazine, 1,8-diazabicyclo [ 5,4,0] Undec-7-ene (1,8-diazabicyclo [5,4,0] undec-7-ene), dimorpholino dimethyl ether, dimorpholino dimethyl ether A group of dimorpholinodiethylether (DMDEE) and mixtures thereof.

In this case, based on the total weight of the composition, the amount of the catalyst is preferably 0.01 to 5 wt.%, And particularly preferably 0.05 to 2 wt.%.

The invention also relates to a polyurethane adhesive, which can be obtained by reacting the polyester polyol of the invention with an isocyanate component. The isocyanate component is preferably one of these compounds, in any case, in particular 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate Or mixtures and / or oligomers thereof. In another preferred embodiment, the polyester polyol of the present invention is reacted with the isocyanate component in the presence of a catalyst (as described above).

In this case, the reaction can be performed under various common conditions well known to those skilled in the art.

Prior to curing, the polyurethane adhesive of the present invention has a viscosity of 1000 to 30,000 mPas, more preferably 1200 to 25,000 mPas, as measured at 75 ° C.

The polyurethane adhesive of the present invention is characterized by many excellent properties, especially high tensile strength and elongation at break after curing. In a preferred embodiment, the polyurethane adhesive of the present invention has a tensile strength of 1 to 60N, preferably 2 to 45N, as measured according to ISO 527-1 after curing. After being completely cured, the elongation at break is preferably 7.0 to 650%, particularly preferably 7.5 to 600%, as measured in accordance with ISO 6922. In this case, the polyurethane adhesive is preferably cured by moisture crosslinking.

According to the invention, the polyurethane adhesive can be used in some manufacturing processes. Therefore, the present invention also relates to the use of the polyurethane adhesive of the present invention in the manufacture of some parts. The adhesive of the present invention is preferably used as a hot-melt adhesive. The use of the adhesive of the present invention is particularly preferably used for manufacturing smartphones and tablets.

The present invention further relates to the use of the polyester polyol of the present invention in an adhesive composition, especially in an adhesive composition within the scope of the present invention.

The polyester polyol of the present invention is particularly suitable for use in some adhesive compositions. Therefore, the present invention also relates to a bonding method, which includes the following steps: (a) providing a mixture including the polyester polyol and an isocyanate component of the present invention; (b) applying the mixture of step (a) to the At least one substrate surface to be bonded, (c) bonding the surface of the substrate to be bonded within an open time, and (d) curing the coated mixture.

In step (a), the mixture is preferably the adhesive composition of the present invention.

The invention will be described in more detail with reference to the following examples, which are not to be understood as limiting the concept of the invention.

The acid number is determined in accordance with DIN EN ISO 2114.

The number of OH groups is determined according to DIN 53240-2.

The viscosity was measured by Brookfield (Thermosel), spindle 27 (spindle 27) at 10 revolutions / minute.

The tensile strength is measured according to ISO 527-1.

The elongation at break is measured in accordance with ISO 6922.

Raw materials used: Diethylene glycol (BASF SE, Germany), Mw 106.12 g / mol propylene glycol (BASF SE, Germany), Mw 76.11 g / mol phthalic acid ( Sigma Aldrich, Germany), Mw 166.13g / mol Capa 2067A (Croda, Germany), OHZ 168-177 Capa 2205 (Croda, Germany), OHZ 54 -58 (ASTM D4274-94d) Polyether polyol (Pluronic) PE 3100 (BASF Europe, Germany), Mw 1000g / mol P-THF 1000 (BASF Europe, Germany), OHZ 107-118 (DIN 53240) Desmodur 44 MC sheet (Covestro, Germany), NCO content (theoretically): 33.6wt.%

Example 1:

A 5 l flask was charged with 1300 g of phthalic acid and 1250 g of propylene glycol. The reaction mixture was heated to 190 ° C under a stream of nitrogen. When the temperature was reached, 0.5 g of tetraisopropyl titanate (T i PT) was added. After a total of 8 hours, an acid value of 0.5 mg KOH / g was reached. The number of OH groups was determined using 426 mg KOH / g. The measured viscosity at 25 ° C was 2500 mPas.

1358 g of an ethylene oxide-propylene oxide segment copolymer ("polyether polyol PE 3100") was added to 215 g of this polyester. The reaction mixture was heated to 220 ° C under a stream of nitrogen. When the temperature was reached, 0.5 g of T i PT was added. After a total of 8 hours of transesterification, the following characteristics were determined:

Acid value: 0.8mg KOH / g

Number of OH groups: 62mg KOH / g

Viscosity: 2500mPas at 25 ℃

The polyester and 4,4'-MDI of the present invention react at a ratio of 2.2: 1 at 130 ° C under vacuum for 1.5 hours to form a polyurethane prepolymer with NCO as the end. Measured at 75 ° C, the viscosity is 1250 mPas.

After the 100 μm thick film of this adhesive was completely moisture crosslinked, the following data was measured:

Tensile strength: 2.5N

Elongation at break: 7.5%

Example 2:

3000 g of PPG 1000 was added to 322 g of a polyester composed of phthalic acid and propylene glycol. The reaction mixture was heated to 230 ° C under a stream of nitrogen. When the temperature was reached, 0.5 g of T i PT was added. After a total of 8 hours of transesterification, the following characteristics were determined:

Acid value: 0.3mg KOH / g

Number of OH groups: 72mg KOH / g

Viscosity: 3000mPas at 25 ℃

The polyester and 4,4'-MDI of the present invention react at a ratio of 2.2: 1 at 130 ° C under vacuum for 1.5 hours to form a polyurethane prepolymer with NCO as the end. Measured at 75 ° C, the viscosity was 3500 mPas.

After the 100 μm thick film of this adhesive was completely moisture-crosslinked, the following data was measured:

Tensile strength: 6.9N

Elongation at break: 250%

Example 3:

A 5 l flask was charged with 1992 g of phthalic acid (PA), 840 g of ethylene glycol (DEG) and 840 g of propylene glycol (PG). The reaction mixture was heated to 190 ° C under a stream of nitrogen. When the temperature was reached, 0.5 g of (tetraisopropyl titanate) TiPT was added. After a total of 8 hours, an acid value of 0.7 mgKOH / g was reached. The number of OH groups was determined using 242 mg KOH / g.

3000 g of P-THF 1000 was added to 322 g of a polyester consisting of PA, DEG and PG. The reaction mixture was heated to 230 ° C under a stream of nitrogen. When the temperature was reached, 0.5 g of T i PT was added. After a total of 8 hours of transesterification, the following characteristics were determined:

Acid value: 0.2mg KOH / g

Number of OH groups: 49mg KOH / g

Viscosity: 11,500mPas at 30 ℃

The polyester and 4,4'-MDI of the present invention react at a ratio of 2.2: 1 at 130 ° C under vacuum for 1.5 hours to form a polyurethane prepolymer with NCO as the end. The viscosity was measured at 75 ° C and was 11,500 mPas.

After the 100 μm thick film of this adhesive was completely moisture-crosslinked, the following data was measured:

Tensile strength: 30N

Elongation at break: 600%

Example 4:

874 g of Capa 2067A and 950.1 g of Capa 2205 were added to 489.6 g of the polyester consisting of PA and PG from Example 1. The reaction mixture was heated to 230 ° C under a stream of nitrogen. When the temperature was reached, 0.5 g of T i PT was added. After a total of 8 hours of transesterification, the following characteristics were determined:

Acid value: 0.1mg KOH / g

Number of OH groups: 55mg KOH / g

Viscosity: 14,000mPas at 25 ℃

The polyester and 4,4'-MDI of the present invention react at a ratio of 2.2: 1 at 130 ° C under vacuum for 1.5 hours to form a polyurethane prepolymer with NCO as the end. The viscosity was 21,500 mPas when measured at 75 ° C.

After the 100 μm thick film of this adhesive was completely moisture-crosslinked, the following data was measured:

Tensile strength: 40N

Elongation at break: 550%

These results are presented in Table 1.

As these examples show, the polyester polyol of the present invention can be obtained by a simple reaction, which makes the use of flammable substances unnecessary. The polyester polyol has a viscosity which allows the product to be easily handled. In addition, various adhesives prepared from the polyester polyols of the present invention have demonstrated good tensile strength and high elongation at break.

Claims (15)

    A low-viscosity polyester polyol, characterized in that the polyester polyol is formed by a transesterification reaction of an ester (A) and a polyol (B), and the ester (A) is formed by at least one benzene Dicarboxylic acid-based materials are formed by reaction with at least one polyhydric alcohol.         The polyester polyol described in item 1 of the scope of patent application, characterized in that the polyester polyol has a viscosity of 1000 to 30,000 mPas, preferably 1000 to 15,000 mPas, measured at 25 ° C.         The polyester polyol described in item 1 of the scope of patent application, characterized in that the at least one phthalic acid-based material is selected from the group consisting of phthalic anhydride, phthalic acid, isophthalic acid, and terephthalic acid. Formic acid, phthalic acid, isophthalic acid or methyl ester of terephthalic acid, dimethyl terephthalate, polyethylene terephthalate, trimellitic anhydride ( trimellitic acid anhydride), pyromellitic acid anhydride, maleic acid anhydride and mixtures thereof.         The polyester polyol described in at least one of item 1 or item 2 of the patent application scope, characterized in that the polyester polyol includes 5 to 30 mol.%, Preferably 7 to 15 mol.% Of benzenediol. Formic acid residue.         The polyester polyol described in item 1 of the patent application range is characterized in that, according to DIN 53240-2, the number of OH groups in the polyester polyol is 40 to 100 mg KOH / g, preferably 45 to 80 mg KOH / g.         The polyester polyol according to at least one of the aforementioned patent applications, characterized in that, according to DIN EN ISO 2114, the polyester polyol has an acid value (SZ) of less than 2 mg KOH / g, preferably less than 1 mg KOH / g.         A method for preparing a polyester polyol as described in at least one of items 1 to 6 of the scope of patent application, characterized in that in a first step, a material based on phthalic acid Is esterified with at least one polyhydric alcohol to obtain an ester (A), and in a further step, the obtained ester (A) is reacted with a polyol (B) to obtain the polyester polyol alcohol.         The method according to item 7 of the scope of patent application, characterized in that it does not include the use of an alkoxylation agent, preferably, it is selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide and mixtures thereof A group of people.         The method according to item 7 or item 8 of the scope of patent application, wherein the polyol (B) is selected from the group consisting of a polyether polyol, a polyester polyol, and a mixture thereof.         An adhesive composition includes a polyester polyol as described in at least one of items 1 to 6 of the scope of patent application.         A polyurethane adhesive can be obtained by reacting a polyester polyol as described in at least one of items 1 to 6 of the patent application scope with an isocyanate component.         The polyurethane adhesive according to at least one of the eleventh or the twelfth in the scope of the patent application, wherein the polyester polyol reacts with the isocyanate component in the presence of a catalyst.         A use of a polyurethane adhesive as described in at least one of the 11th or 12th of the scope of patent application, which is used to manufacture parts, especially smart phones and tablet computers.         The use of a polyester polyol as described in at least one of the scope of claims 1 to 6 in an adhesive composition, especially a composition of the adhesive as described in scope 10 of the patent application Uses.         A method for bonding, comprising the steps of: a. Mixing the polyester polyol and an isocyanate component as described in at least one of items 1 to 6 of the scope of patent application, b. Coating the mixture of step a Placed on the surface of at least one substrate to be bonded, c. Bonding within open time, d. Curing the coated mixture.