CS236247B1 - Glycol component of polyesterurethane systems - Google Patents

Abstract

Glycol component of polyesterurethane systems containing 80 to 99 wt. percent glycol and chain length 02-0^2 with primary hydroxyl groups and 1 to 20 wt. percent glycol and chain length C3-C12 with at least one secondary hydroxyl group. By using this glycol component, the processability of polyesterurethane mixtures is achieved at isocyanate ratios deviating from the ideal value by up to ± 4.5%» P*“i maintaining the physical-mechanical values, some of which, e.g. resistance to repeated bending, are even improved.

Description

The invention relates to a glycol component of polyester urethane systems further comprising a polyester oligomer and / or mixtures thereof, in particular polyethylene adipate, polyethylene butylene adipate, polyethylene propylene adipate, polyhexamethylene adipate and diisocyanate, optionally additional agents such as water, catalysts and the like.

In the manufacture of polyesterurethane elastomers, one of three production processes is generally used, for which the names prepolymer, semiprep polymer and disposable have been known in the technical practice. In the prepolymer production process, the polyester oligomer is reacted with an excess amount of diisocyanate and the free isocyanate is reacted in a second step with a low molecular weight glycol containing primary alcohol groups. A disadvantage of the prepolymer process is the considerable disparity between the weight of the two components, which is in the ratio of 10 parts prepolymer to 1 part glycol. Therefore, these processes are only applicable to continuous casting machines.

In the one-shot process, all the components, both the polyester oligomer, the glycol and the isocyanate, respectively. various auxiliary agents such as catalysts, water, detergents, foam stabilizers and chlorinated hydrocarbons are supplied to the mixer simultaneously and cast after mixing. Polyester with glycol can be dosed by one pump and diisocyanate by another so that the weight ratio between the two components is reduced to a ratio of 1: 2 - 1: 5. This already allows for more accurate dosing of both components, but with increasing glycol content problems with different reactivity of polyester and glycol increase.

236 247

In the semi-prepolymer process, part of the polyester oligomer is reacted with all the diisocyanate and the resulting prepolymer serves as the isocyanate component of the systems. The remainder of the polyester oligomer is mixed with the glycol, the catalyst or the catalyst. water, detergents, foam stabilizers and serve as the second component of the reaction system. The polyester is divided between the two components so that the weight ratio of the two components is in the range of 1: 1 to 1: 2, with ratios close to 1: 1 being preferred. The semi-prepolymer system enables very precise adjustment of the weight ratio of both components and its dosing into the machine mixing device. Differences in the reactivity of the polyester and glycols in these systems can be offset by suitable catalysts such as triethylenediamine, dibutylcindilaurate or dibutylcindiacetate.

As can be seen from the description of these methods, in all cases particular emphasis is placed on the dosing accuracy of the individual components.

A measure of dosing accuracy is the ratio of - NCO to --OH groups, which, when multiplied by 100, expresses the isocyanate index. Its ideal value is therefore 100, which in practice is of course difficult or even impossible to keep. However, if, for example, in polyurethanes from which lightweight molded parts are produced by molding, the dosing deviation is greater than 1% deviation from the ideal state, the cracks of parts below 600 kg / m are already cracked after 30,000 cycles and this slope for cracking increases with decreasing the value of the zocyanate module and the bulk density of the part. This is particularly the case for extremely stressed parts, such as shoe soles, the surface of which is permanently disturbed when the sole is stepped on uneven ground, and the sole is permanently bent at each step. The tendency to crack is most pronounced in soles with high elasticity and a degree of lightening of the mushroom sole. In normal industrial production, a large part of the outsole bursts due to existing slight variations in dosing and uneven mixing of the mixture after two to three months of wear and therefore do not comply with the specified standards. These phenomena are believed to be due to the presence of glycols with primary alcohol groups on the carbon chains that promote the formation of hydrogen bonds resulting in the bonding of the hard urethane segment in the polymer via hydrogen bonds.

Described disadvantages are absent in polyesteruretanových systems in which the glycol component used according to the invention comprising 80 to 99 weight percent glycol, a chain length of Cg - C ₁₂ pri- 3,236,247 Marnie hydroxilovými groups and 1 to 20 weight percent of a glycol chain length C 1-6 with at least one secondary hydroxyl group.

An advantage of the invention is that the alkyl group that is bonded to the carbon containing secondary alcohol group behaves as a plasticizer in the resulting polymer because it prevents the formation of hydrogen bridges. This results in higher elasticity, higher ductility, better tear resistance, higher tear resistance, and better resistance to repeated bending and better resistance to crack growth even at reduced temperatures. The processing range is increased to at least -3% compared to the original 1.0%. Therefore, virtually all existing machinery used for metering and mixing polyurethanes is capable of producing parts of the required quality and durability.

Accordingly, the glycol component of the present invention contains from 1 to 20 weight percent of a chain length glycol having a C? G containing at least one secondary hydroxyl group. Typical representatives of these glycols are propanediol-1,2 * butanediol-1,3, * butanediol-2,3; pentane diol-1,3; hexanediol-2,5J hexanediol-1,5; hexanediol-1,4 »Butanediol-1,3; propanediol-1,2 and butanediol-2.3, especially since they are the most commercially available. Using propanediol-1,2 and butanediol-1,3, it is possible to work with limit values ranging from 1 to 20%. With increasing butanediol-1,3 content in combination with butanediol-1,4, the processing range gradually increases from -2.5% to -4.5%.

'As hydroxilovými glycols with primary groups of chain length C ₂ - _C-2 was used in an amount of from 80 to 99 weight percent of conventional glycols such as mono-ethyleneglycol, diethylene glycol, 1,4 - butanediol, 1,6 - hexanediol, neopentyl glycol, dodecane, or mixtures of monoethylene glycol with diethyl glycol. The use of trioles, such as 1,1,1-trimethylolpropane or glycerin (CS 182 088), is also not excluded, as a result of which a branching associated with advantageous reaction rates is generally achieved.

As the polyester component and the isocyanate component, customary compounds are used, in particular polyesters having a molecular weight of 1000-4000, for example from polyester oligomers such as polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polyethylene propanediol-1,2, adipate, polyethylene butylene adipate, polyethylene diethylene adipate.

- 4,238,247

Although the present description is directed to polyester polyurethane systems of expanded molded compositions, the situation with regard to the composition of the polyol component according to the invention also applies to compact polyesterurethane elastomers, whether casting or thermoplastic.

In the following examples, the invention is explained in more detail not only by the composition of the glycoc component, but also by the values obtained.

Examples 1 to 5.

A prepolymer of ethylene butylene adipate and 4,4-diphenylaetane diisocyanate was prepared; content of free -NCO groups = 16.6%. In the polyol component, 1,4-butanediol was used in all examples in combination with 1,3-butanediol (examples 1,3,5) and 2,3-butanediol (examples 2, 4).

The results are arranged in a table by columns

I. to V. for Examples 1 to 5.

Butanediol-1,4 content (%) 97 94 91 82 ⁸⁰ Butanediol content-1,3 (%) 3 0 9 0 20 May Butanediol-2,3 content (%) 0 6 0 18 0 Molding Sas (min.) 3.5 3,5-4,0 4-4, 5 5-5,5 6-6,5 Hardness (° ShA) 45 44 42 40 38 Ductility (%) 550 550 600 650 650 Tensile strength (MPa) 5.7 5.5 5.5 5.4 5.2 Resistance to tear (KNnT ^ -) 13.6 12.8 12.8 12.5 11.9 Tear resistance (KNm ¹ ) 24.2 22.8 22.5 21.5 20.8 Range of isocyanate in- 93-101 94-101 94-102 93-102 93-102

dexu

The last row of all columns shows the values for the usable isocyanate index range. The range, judged by the de MattiaJ method of breaking the test specimen after 30 kc, the crack width was at most 6 mm.

Example 6.

% by weight of prepolymer containing 16.6% free -NCO groups was mixed with 100 parts by weight of a polyol blend having the following composition:

parts by weight of 2000 ethylene butylene adipate,

- 5 236 247

0.9 parts by weight 10.0 parts by weight

0.35 parts by weight 0.5 parts by weight 0.05 parts by weight

1.5 - hexanediol,

1.6 - hexanediol, water, triethylenediamine, dibutylcinlaurate.

ie 8.2%,

By mutual reaction, polyurethane foam was produced for the production of 2 soles, which at the density of 600 kg / m exhibited the following mechanical-physical properties:

Tensile strength (MPa) 6.0

Ductility (%) 600

Hardness (ShA) 41

Tear resistance (KNm ^- ^) Tear resistance (KNm ”^)

Isocyanate index range (30,000 cycles, crack width 6

11.8

22.7

- 100 mm).

Example 7.

A prepolymer prepared from diphenylmethane diisocyanate and a polyester polyol prepared from adipic acid and a mixture of monoethylene glycol with diethylene glycol of an average weight of 2000, containing 19% of the free -NCO groups, are mixed with a polyol component of the following composition:

parts by weight of 2000 molecular weight diethylene adipate,

3,6 parts by weight of 2,4 - heptanediol, ie 14,6%,

21.0 parts by weight of 1.10 dodecanediol,

0.4 parts by weight of water,

0,5 parts by weight of petroleum jelly,

0.7 parts by weight of triethylenediamine.

By reacting the components, a polyurethane foam having the following mechanical-physical properties is obtained:

β Bulk density (kg (nr)) 600 Tensile strength (MPa) 3.5 Ductility (%) 750 Resistance in further tearing (KNm ” ¹ ) 9.3 Tear resistance (KNm ’^) 19.2 Hardness (ShA) 36 Rožbah isocyanot index 92 ·

(at 30 kc crack width <6 mm)

- 6 ^Example θ _'23β 247

An ethyl prepolymer was prepared from 100 parts by weight of polyethylene adipate having an average molecular weight of 2,000 and from 40 parts by weight of 4,4-diphenylmethane diisocyanate. To this was added a mixture. glycol, consisting of 6.2 parts by weight of 1,4-butanediol and 1.0 parts by weight of 1,3-butanediol. After mixing with one another, a polymer was obtained from which the prepared granules were used for the production of soles by injection molding in the processing temperature range from 170 to 190 ° C.

The following values of mechanical-physical properties were measured in the resulting footwear:

Tensile strength (MPa) 38

Elongation (%) 680

Tear Strength 140 (kNa " ^x )

Structure strength in the next 120 tearing (kNm ¹ )

Hardness (ShA) 70

Abrasion (mm ^) 33 ·

Example 9.

Of a mixture of 60 parts by weight of polyethylene butylene adipate with a molecular weight of 2,000 and 80 parts by weight of 4,4-diphenylmethane diisocyanate and a polyol component consisting of 40 parts by weight of polyethylene butylene adipate * with a molecular weight of 2,000, 4.5 parts by weight of 1,3-butanediol and 18 1.8 parts by weight of 1,4-butanediol were prepared by granules and injection molded by bolts at processing temperatures ranging from 175 to 195 ° C.

Values of measured mechanical-physical properties:

Tensile strength (MPa)

Elongation (%) 450

Tear strength 200 (kNm-1)

Structural strength in 180 additional tearing (kNm-1)

Hardness (Sfyft)

Claims (1)

SUBJECT OF THE INVENTION 236 247 The glycol component of polyester urethane systems, further comprising a polyester oligomer and / or mixtures thereof, in particular polyethylene adipate, polyethylene butylene adipate, polyethylene propylene adipate, polydiethylene glycoladipate, polybutylene adipate, polyhexamethylene adipate and diisocyanate, and the like, is an additional agent, it contains 80 to 99% by weight of glycols of chain length ^C 2 ^C 12 with primary hydroxyl groups and 1 to 20% by weight of glycols of chain length - ₁₂ with at least one secondary hydroxyl group.