KR20090017123A - Thermoplastic polyurethane having good flame-retardant property and their preparation - Google Patents

Abstract

Thermoplastic polyurethane is provided to prevent the fire due to high oxygen index, and to reduce the generation of noxious gas because a halogen element is not contained, while having the self-extinguish stability after firing. Flame retardant characteristic thermoplastic polyurethane comprises organic diisocyanates, Long-chain diols, a chain extender, and a mixture of melaminecyanurate and phosphinate indicated as the chemical formula 1 as a flame retardant. The melaminecyanurate is contained in the amount more than 25 parts by weight, based on the solid content 100 parts by weight of thermoplastic polyurethane. In the chemical formula 1, R1 and R2 are the same or different, show C1-6 linear or branched alkyl or aryl group; M is calcium, aluminium or zinc ion; and m is 2 or 3.

Description

Flame-retardant thermoplastic polyurethane and method for producing the same {Thermoplastic polyurethane having good flame-retardant property and their preparation}

The present invention relates to a flame retardant thermoplastic polyurethane and a method for producing the same.

Polymers, commonly referred to as polyurethanes or urethane polymers, have a fairly wide range of applications. In terms of its use, it is no exaggeration to say that it is commonly used in almost all fields of polymer materials such as elastomers, flexible foams, rigid foams, plastics, paints, adhesives, fibers, and synthetic leathers.

In terms of structure, it is not valid to call all products polyurethane. In general, urethane groups are rather small compared to other structural units, and the structure of the portion other than the urethane group varies widely. Due to the variety of structures, the properties of urethane polymers are varied, which allows for a wide range of applications and complicates the structural relationships of polyurethanes.

Among them, thermoplastic polyurethane (hereinafter referred to as TPU) is very important in the industry because of its excellent elastomeric properties and thermoplastic processability. An overview of the manufacture, properties and uses of TPUs is well known in the literature (eg Kunststoff Handbuch, G. Becker, D. Braun, volume 7 "Polyurethane", Munich, Vienna, Carl Hanser Verlag. 1983). ).

The TPU may basically comprise a three component compound, which may include organic diisocyanates; A long-chain diols such as polyester diols, polyether diols, polycarbonate diols, and the like; And A short-chain diols, usually difunctional alcohols (ie, chain extenders). TPU can be prepared continuously or discontinuously using such compounds.

Such thermoplastic polyurethanes are inherently flammable as in most plastics, and in this regard, stability to flame, that is, flame retardancy is often required.

Halogen-based organic compounds have been used as flame retardants to meet these demands, but halogen-based flame retardants have problems such as large amounts of smoke during combustion and corrosion of metals.

To this end, efforts have been made to use flame retardants that do not contain any halogen compounds. For example, U.S. Patent No. 5,837,760 uses organic phosphate and / or organic phosphonate as a flameproofing agent. Thermoplastic polyurethanes with a mixture of melamine cyanurates are described. However, this had a problem of insufficient flame retardancy.

The present invention is to provide a thermoplastic polyurethane having self-extinguishing and excellent flame retardancy.

In the present invention, in one embodiment for achieving the above object, in the thermoplastic polyurethane comprising organic diisocyanates, long chain diols and chain extenders as necessary, as a flame inhibitor, phosphinic acid represented by the following formula (1) And a mixture of salt and melamine cyanurate, wherein the melamine cyanurate provides a flame retardant thermoplastic polyurethane, characterized in that at least 25 parts by weight relative to 100 parts by weight of the thermoplastic polyurethane solids content.

Wherein R ₁ and R ₂ are the same as or different from each other, and are a linear or branched alkyl group or an aryl group having 1 to 6 carbon atoms; M is calcium, aluminum or zinc ions; m is 2 or 3.

In a preferred embodiment of the present invention, the phosphinic acid salt represented by Formula 1 may be M is aluminum ions.

In a preferred embodiment of the present invention, the melamine cyanurate may be included in an amount of 25 parts by weight to 40 parts by weight based on 100 parts by weight of the thermoplastic polyurethane solid content.

In a preferred embodiment of the present invention, the phosphinic acid salt represented by Formula 1 may be included in an amount of 15 parts by weight to 25 parts by weight based on 100 parts by weight of the thermoplastic polyurethane solid content.

In one preferred embodiment of the present invention, the phosphinic acid salt represented by the formula (1) is contained in 15 parts by weight to 25 parts by weight with respect to 100 parts by weight of the thermoplastic polyurethane solids content, melamine cyanurate is 100 parts by weight of the thermoplastic polyurethane solids content 25 parts by weight to 40 parts by weight with respect to parts by weight may be included.

In another embodiment of the present invention, an additive and a necessity including organic diisocyanates and long chain diols and, if necessary, a chain extender, a mixture of a salt of phosphinic acid represented by the following formula (1) with melamine cyanurate The present invention provides a method for producing a flame retardant thermoplastic polyurethane comprising the step of reacting in the presence of a catalyst.

Formula 1

Wherein R ₁ and R ₂ are the same as or different from each other, and are a linear or branched alkyl group or an aryl group having 1 to 6 carbon atoms; M is calcium, aluminum or zinc ions; m is 2 or 3.

In another embodiment of the present invention is a process for producing a polyurethane by polymerizing a composition comprising organic diisocyanates and long-chain diols and, if necessary, a chain extender, in the presence of a catalyst, if necessary; And compounding an additive comprising a mixture of a salt of phosphinic acid represented by the formula (1) and a melamine cyanurate, to the polyurethane.

Formula 1

Wherein R ₁ and R ₂ are the same as or different from each other, and are a linear or branched alkyl group or an aryl group having 1 to 6 carbon atoms; M is calcium, aluminum or zinc ions; m is 2 or 3.

The thermoplastic polyurethane according to the present invention has a high oxygen index, which makes it difficult to ignite during a fire and has self-extinguishing ability even after ignition, and does not contain halogen elements, thus reducing the generation of harmful gases, which is useful for producing environmentally friendly flame retardant products.

Polyurethane according to the present invention comprises a mixture of an organic phosphinic acid salt and melamine cyanurate as a flame retardant, the organic phosphinic acid salt is represented by the following formula (1).

Formula 1

Wherein R ₁ and R ₂ are the same as or different from each other, and are a linear or branched alkyl group or an aryl group having 1 to 6 carbon atoms; M is calcium, aluminum or zinc ions; m is 2 or 3.

Specifically, the organic phosphinic acid salt may be aluminum phosphinate, calcium phosphinate or zinc phosphinate. Specifically, in Formula 1, M is aluminum phosphinate.

In the present invention, the amount of the organic phosphinic acid salt added is preferably 15 parts by weight or more, preferably 15 to 25 parts by weight based on the total solids content of the diisocyanates and diols, that is, the polyurethane solids, in terms of self-extinguishing property. Do. Herein, the total solid content of diisocyanates and diols may be defined as the total solid content of organic diisocyanates and long chain diols used in the preparation of the thermoplastic polyurethane of the present invention and the chain extender added as necessary. have.

However, if only the organic phosphinic acid salt is applied alone as a flame retardant, the flame retardancy can be satisfied when used in excess, but since a lot of drips occur during the combustion process, the combustion sparks show a lot of dropping, so the transition of fire There may be a problem that becomes easier, for this purpose, melamine cyanurate is used in the present invention.

Melamine cyanurate has conventionally been used as a flame retardant such as thermoplastic polyurethane, but it is difficult to obtain improved flame retardancy only by using it alone.

The amount of melamine cyanurate added should be 25 parts by weight or more based on the total solid content of diisocyanates and diols to impart self-extinguishing. If the content is less than 25 parts by weight, the organic phosphinic acid salt is not added in excess. Otherwise, once the fire has started, it will not be extinguished and burned out, which can have a bad effect in case of fire. More preferably, 25 parts by weight to 40 parts by weight is advantageous in that the mechanical properties can be lowered and the flame retardancy can be lowered compared to the addition of other phosphorus-based or inorganic flame retardants.

In general, thermoplastic polyurethanes are obtained by reacting organic diisocyanates with long-chain diols, and may include a chain extender as necessary.

First, as organic diisocyanates, aromatic, aliphatic and cycloaliphatic diisocyanate compounds can be used, for example, 2,4-toluylene diisocyanate, 2,6-toluylene diisocyanate, phenylene diisocyanate, 4 , 4'-diphenyl methane diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-dimethyl biphenyl-4,4'- diisocyanate, o-, m- Or diisocyanates such as p-xylene diisocyanate, tetra methylene diisocyanate, hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, dodecane methylene diisocyanate, cyclohexane diisocyanate and dicyclohexyl methane diisocyanate.

First of all, long chain diols for forming soft segments to impart flexibility in the production of thermoplastic polyurethane are not particularly limited, and may be polyester diols, polycaprolactone diols, polyether diols, polycarbonate diols, or mixtures thereof. Can be. Specifically, ethylene glycol, trimethylene glycol, tetramethylene glycol, hexene glycol, propylene glycol, and the like, adipic acid, succinic acid, glutaric acid, subberic acid, sebacic acid, etc. which are saturated aliphatic dicarboxylic acids having 4 to 10 carbon atoms; Condensates obtained from phthalic acid, isophthalic acid, terephthalic acid and the like which are aromatic dicarboxylic acids; Copolymers of alkylene glycols with lactone groups and thus obtained polyester glycols such as polylactone diols, polycaprolactone diols, and the like; Or condensates of alkylene oxides having 2 to 4 carbon atoms; Condensates of alkylene oxides having 2 to 4 carbon atoms with alkylene glycols; Polyalkylene glycols having 2 to 4 carbon atoms; Polyalkylene ether glycols obtained by ring-opening polymerization of tetrahydrofuran or the like; Dihydroxy polyalkylenes; Or hydroxy polycarbonates can also be used.

More specifically, polytetramethylene ether glycol, dihydroxy polyethylene adipate, polyethylene glycol, polypropylene glycol, etc. are mentioned.

Such long chain diols may have a weight average molecular weight of about 500 to about 8000, and another example may be about 500 to about 2800.

Meanwhile, if necessary, short chain diols may be included as a chain extender. Examples thereof include saturated aliphatic glycols having 2 to 6 carbon atoms, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and butane 1 , 2-diol, butane 1,3-diol, butane 1,4-diol, butane 2,3-diol, butane 2,4-diol, hexane diol and the like, and 1,4-xylene which is an aromatic glycol Glycol, phenylene bis- (β-hydroxy ethyl ether), and the like.

In addition, for example, a small amount of trifunctional or higher alcohols such as trimetholpropane, glycerin, hexane triol and the like can be used simultaneously.

The content of long chain diols and chain extenders can be adjusted to obtain the required hardness and melt flow index. The hardness and melt viscosity increase with increasing chain extender content, while the melt flow index tends to decrease. Indicates.

For example, in order to satisfy the hardness level and the viscosity level suitable for coating the optical cable, the molar ratio of the long-chain diol and the chain extender may be adjusted to be about 1: 1 to 1:15, and another example may be 85 (Shore A) to 70 (Shore). In order to satisfy the hardness level and the viscosity level suitable for D), the molar ratio of the long chain diol and the chain extender may be adjusted to be about 1: 1.2 to 1:13.

In addition, the thermoplastic polyurethane according to the present invention may be used for the production of lubricants, hydrolysis stabilizers, light stabilizers, heat stabilizers, anti-pigmentation stabilizers, dyes, pigments, inorganic and / or organic fillers and reinforcing agents. Adjuvants and / or additives, such as, for example, may further include.

On the other hand, the production of the thermoplastic polyurethane of the present invention, a long chain diols, organic diisocyanates and, if necessary, a chain extender, a mixture of an organic phosphinic acid salt represented by the formula (1) and melamine cyanurate represented by the formula (1) as a flame retardant and Reacting in the presence of a catalyst, if necessary, auxiliaries and / or additives as described above, wherein the equivalent ratio of the sum of the NCO group of the organic diisocyanate and the hydroxyl group of the long chain diols and the chain extender is 0.99: 1 to 1.07: 1 It can be done so that it is raining.

Another industrially more useful method is the compounding method, for example, from a composition comprising organic diisocyanates and long chain diols and, optionally, chain extenders, if necessary polymerized in the presence of a catalyst to After preparing the urethane, a mixture of the organic phosphinic acid salt represented by the formula (1) and melamine cyanurate may be compounded therein. Of course, the above-mentioned auxiliary agent and / or additives can be further added during the polyurethane polymerization.

The thermoplastic polyurethane obtained may have a number average molecular weight of at least 100,000 to 400,000.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1

150 g of polytetramethylene ether glycol (weight average molecular weight 1,000), 21.7 g of butane 1,4-diol, 110 g of melamine cyanurate, and an organic phosphinate salt (in Formula 1, R ₁ is an ethyl group and R ₂ is a methyl group). 55 g of M), a compound of aluminum), was weighed and stirred for 5 minutes, and then maintained at 80 ° C. Then, 103.7 g of 4,4'-diphenylmethane diisocyanate was added and stirred for 2 minutes to obtain a polymerization reaction.

The obtained polymerized product was pulverized and injected to prepare a specimen, and flame retardancy evaluation was performed. The results are shown in Table 2 below.

Flame retardancy evaluation was expressed as an oxygen index (LOI) value measured according to ASTM D2863.

Examples 2-9

A thermoplastic polyurethane specimen was obtained in the same manner as in Example 1, except that melamine cyanurate and the organic phosphinate compounded amount were changed as shown in Table 1 below to obtain a polymerization product.

The obtained polymerization reaction was pulverized and then injected to prepare a specimen. The flame retardancy evaluation was performed in the same manner as in Example 1, and the results are shown in Table 2 below.

Comparative Example 1

A thermoplastic polyurethane specimen was obtained in the same manner as in Example 1 except using an organic phosphate compound (1,3-phenyl tetraphenyl phosphate) instead of an organic phosphinic acid salt to obtain a polymerization product.

The obtained polymerization reaction was pulverized and then injected to prepare a specimen. The flame retardancy evaluation was performed in the same manner as in Example 1, and the results are shown in Table 2 below.

Comparative Example 2

A thermoplastic polyurethane specimen was obtained in the same manner as in Example 1, except that an organic reaction product was obtained without adding an organic phosphinate.

The obtained polymerization reaction was pulverized and then injected to prepare a specimen. The flame retardancy evaluation was performed in the same manner as in Example 1, and the results are shown in Table 2 below.

Comparative Example 3

A thermoplastic polyurethane specimen was obtained in the same manner as in Example 1, except that melamine cyanurate was not added to obtain a polymerization product.

The obtained polymerization reaction was pulverized and then injected to prepare a specimen. The flame retardancy evaluation was performed in the same manner as in Example 1, and the results are shown in Table 2 below.

Comparative Examples 4 to 5

A thermoplastic polyurethane specimen was obtained in the same manner as in Example 1, except that melamine cyanurate and the organic phosphinate compounded amount were changed as shown in Table 1 below to obtain a polymerization product.

The obtained polymerization reaction was pulverized and then injected to prepare a specimen. The flame retardancy evaluation was performed in the same manner as in Example 1, and the results are shown in Table 2 below.

Melamine cyanurate addition amount (part by weight) Organic phosphinic acid salt addition amount (part by weight) Example 1 40 20 Example 2 40 15 Example 3 30 20 Example 4 40 10 Example 5 35 15 Example 6 35 12 Example 7 35 10 Example 8 40 18 Example 9 30 18 Comparative Example 4 20 15 Comparative Example 5 15 15

In Table 1, the addition amount is expressed in parts by weight based on 100 parts by weight of the total solid content of diisocyanates and diols.

Examples 10 to 18

Thermoplastic polyurethane specimens were obtained in the same content ratios as in Examples 1 to 9, except that the preparation method was changed as follows.

First, an organic diisocyanate and a diol were reacted for 2 minutes to polymerize a polyurethane, and an organic phosphinic acid salt and melamine cyanurate were added thereto, followed by compounding extrusion to obtain a thermoplastic polyurethane specimen of the present invention.

The flame retardancy evaluation was performed for this and the results are shown in Table 3 below.

division Oxygen Index (%) Example One 32 2 30.5 3 28.2 4 28 5 27.5 6 26.5 7 26 8 31 9 28.1 10 31.5 11 29.5 12 28 13 27.5 14 27 15 26 16 25.5 17 30 18 28 Comparative Example One 23 2 22 3 - 4 - 5 -

* Symbol (-): Indicates that the unit is not extinguished and continues to burn

From the results in Table 2, as in Examples 1 to 18, including the organic phosphinic acid salt and melamine cyanurate as a flame retardant, especially melamine cyanurate is more than 25 parts by weight based on 100 parts by weight of polyurethane solids content melamine Compared with the case containing cyanurate alone or the organic phosphinic acid salt alone, it is excellent in flame retardancy to self-extinguishing, and it turns out that a flame retardance improves also compared with what used the organic phosphonate compound.

Preferably it contains more than 25 weight part of organic phosphinic acid salt, while including melamine cyanurate 25 weight part or more with respect to 100 weight part of polyurethane solid content, More preferably, melamine cyanurate 25-40 It can be seen that it contains by weight and 15 to 25 parts by weight of the organic phosphinic acid salt.

Claims (7)

In the thermoplastic polyurethane containing organic diisocyanates, long chain diols and chain extenders as needed, Flame retardant, comprising a mixture of phosphinic acid salt and melamine cyanurate represented by the following formula (1), characterized in that the melamine cyanurate comprises at least 25 parts by weight based on 100 parts by weight of the thermoplastic polyurethane solid content Flame retardant thermoplastic polyurethane. Formula 1

Wherein R ₁ and R ₂ are the same as or different from each other, and are a linear or branched alkyl group or an aryl group having 1 to 6 carbon atoms; M is calcium, aluminum or zinc ions; m is 2 or 3. The method according to claim 1, The phosphinic acid salt represented by the formula (1) is flame retardant thermoplastic polyurethane, characterized in that M is an aluminum ion. The method according to claim 1 or 2, Flame retardant thermoplastic polyurethane, characterized in that the melamine cyanurate is contained in an amount of 25 to 40 parts by weight based on 100 parts by weight of the thermoplastic polyurethane solids content. The method according to claim 1 or 2, The phosphinic acid salt represented by the formula (1) is 15 to 25 parts by weight based on 100 parts by weight of the thermoplastic polyurethane solids content, flame retardant thermoplastic polyurethane. The method according to claim 3, The phosphinic acid salt represented by the formula (1) is 15 to 25 parts by weight based on 100 parts by weight of the thermoplastic polyurethane solids content, flame retardant thermoplastic polyurethane. Reacting the organic diisocyanates with the long chain diols and, if necessary, the chain extender in the presence of a catalyst, an additive comprising a mixture of a salt of phosphinic acid represented by the following formula A method for producing a flame retardant thermoplastic polyurethane comprising a step. Formula 1

Wherein R ₁ and R ₂ are the same as or different from each other, and are a linear or branched alkyl group or an aryl group having 1 to 6 carbon atoms; M is calcium, aluminum or zinc ions; m is 2 or 3. Polymerizing a composition comprising organic diisocyanates and long chain diols and, if necessary, a chain extender, in the presence of a catalyst, if necessary, to produce a polyurethane; And A method for producing a flame retardant thermoplastic polyurethane comprising the step of compounding a polyurethane with an additive comprising a mixture of a salt of phosphinic acid represented by the formula (1) with melamine cyanurate. Formula 1

Wherein R ₁ and R ₂ are the same as or different from each other, and are a linear or branched alkyl group or an aryl group having 1 to 6 carbon atoms; M is calcium, aluminum or zinc ions; m is 2 or 3.