GB2190388A

GB2190388A - Polyamides and thixotropic compositions containing them

Info

Publication number: GB2190388A
Application number: GB08607788A
Authority: GB
Inventors: Alec Frank Wilson
Original assignee: Coates Brothers and Co Ltd
Current assignee: Coates Brothers and Co Ltd
Priority date: 1986-03-27
Filing date: 1986-03-27
Publication date: 1987-11-18
Also published as: EP0239419A2; GB8607788D0; EP0239419A3; GB2188330A; GB2188330B; GB8707204D0

Abstract

Polyamide resins, useful for imparting thixotropy to organic solvents and compositions comprising film- forming resins dissolved in organic solvents, are derived from (a) an amine component comprising: (i) an aliphatic diamine; (ii) an ether monoamine, an ether diamine or an ether triamine; and, optionally, (iii) a monoamine other than an ether monoamine; and (b) an acid component comprising: (iv) an organic dicarboxylic acid; and, optionally, (v) an organic monocarboxylic acid. n

Description

1

GB 2 190 388A 1

SPECIFICATION

Polyamides and thixotropic compositions containing them

5 This invention relates to polyamide resins and thixotropic compositions containing them.

The production of thixotropic vehicles for use in paints and other surface coating compositions by incorporating polyamide resins into certain types of surface coating vehicles at elevated temperatures, e.g. 220-260°C, is well known. The polyamide resins used typically have molecular weights of from 3,000 to 9,000, are prepared by the reaction of dimerised and/or trimerised 10 fatty acids with alkylene polyamines, and typically have acid and amine values of from 2-4 mgKOH/g.

In the manufacture of a thixotropic vehicle in this known manner, a surface coating vehicle containing ester groups is first prepared and then compounded with the polyamide resin at elevated temperature. This requires the application of substantial heat and careful control over 15 the processing because if heating is continued after maximum thixotropy has developed this property rapidly falls off. In addition, at the processing temperatures employed, there is a tendency for the surface coating vehicle itself to polymerise. This complicates the operation because the surface coating vehicle has to be prepared with properties such that it acquires the desired degree of polymerisation simultaneously with the attainment of maximum thixotropy of 20 the mixture. With certain heat sensitive vehicles, such as urethane oils and alkyds, high temperature reactions are not possible and other means of achieving thixotropy have to be employed.

In British Patents 992311 and 1003029, there is described the preparation of a concentrated thixotropic polyesteramide or "thixogen", which thixogen can be used with a variety of surface coatings to produce a thixotropic coating composition by simply warming it in the composition 25 to dissolve it therein. Whilst this is a relatively simply technique and overcomes many of the disadvantages associated with the more conventional method, in practice it is difficult to ensure reproducible manufacture of the concentrated thixotropic vehicle. Thus, in practice it is found that the thixotropy obtained is highly dependent on the reaction time and/or temperature employed in the manufacture of the polyesteramide thixogen. This variability of performance is 30 probably due to interchange reactions which result in differences in location of ester and amide groups in the molecule. This in turn affects the solubility of the resin and the level of thixotropy obtained.

It has now been found, in accordance with the present invention, that certain polyamides, as hereinafter defined, may be reproducibly manufactured by a simple technique and may be used 35 to impart thixotropy to a wide variety of organic liquid materials by simple dissolution therein.

According to the invention, there is provided a polyamide derived from:

(a) an amine component comprising

(i) an aliphatic diamine;

(ii) an ether monoamine, an ether diamine or an ether triamine; and optionally 40 (iii) a monoamine other than an ether monoamine; and

(b) an organic carboxylic acid component comprising:

(iv) an organic dicarboxylic acid; and, optionally,

(v) an organic monocarboxylic acid.

The polyamides of the invention may be prepared in a simple manner and the resulting 45 thixotropy obtained by use of such products has been found to be relatively independent of the reaction time and/or temperature employed in the manufacture of the polyamides.

An essential feature of the polyamides of the invention is that, in addition to the amines and acids commonly used in the preparation of thixogenic polyamides, they are also derived from an ether amine, by which term is meant an amine containing a hydrocarbon chain interrupted by 50 one or more oxygen atoms or containing an oxygen-containing heterocyclic ring.

Suitable ether monoamines may be represented by the formula:

R—O—R1—NH2 (I)

in which R is an alkyl group and R1 is an alkylene group. Examples of such monoamines are 3-stearyloxy-propylamine, 3-methoxy-propylamine, 3-ethoxy-propylamine and 3-(2'-ethylhexoxy)-pro-55 pylamine.

Suitable ether diamines include polyoxyalkylene diamines of the formulae:

H2N-R1-(OR2)nNH2 (II)

and

H2N-R1-(OR2)a-(OR3)b-(OR2)c-NH2 (III)

60 in which R1 is an alkylene group and R2 and R3 are different and each is an ethylene or propylene group and n, a, b and c indicate that the groups -OR2- or -OR3- may be present, on average, more than once. Specific examples of such polyoxyalkylene diamines are the products sold by Texaco under the trade designation "Jeffamine D" (formula II, R1=R2=isopropylene), e.g. Jaffamine D-230 (n = 2.6), Jeffamine D-400 (n = 5.6); and the products sold by Texaco 65 under the trade designation "Jeffamine ED" (formula III, R1=R2=isopropylene, R3=ethylene), e.g.

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GB 2 190 388A 2

Jeffamine E-600 (a+c=3.5, b=13.5), Jeffamine ED-900 (a+c=3.5, b=20.5), Jeffamine ED-2001 (a+c=3.5, b=45.5), Jeffamine ED-4000 and Jeffamine ED-6000.

Other suitable ether diamines of the formula:

H2N—R1—O—R4—O—Ft5—NH2 (IV)

5 (in which R1, R4 and R5 are each alkylene groups), such as 4,9-dioxa-dodecan-1,12-diamine; and 5 diamines containing oxygen-containing heterocyclic groups of the formula

H2N-R1(R6)„-R4NH2 (V)

in which R1 and R4 are each alkylene groups, R6 is an oxygen-containing heterocyclic group such as tetrahydrofuran ring, and n indicates that the groups R6 may be present, on average, more 10 than once. Specific examples of the diamines of formula V are the bis-3-aminopropyl polytetrahy- 10 drofurans sold by BASF having average molecular weights of 750, 1100 and 2100.

Suitable ether triamines are polyoxyalkylene triamines of the formula:

15 (0R2)xNH2 R7 (OR2) NH„

y 2

(VI)

15

20 ^ (OR2) NH2 20

in which R7 is a trivalent aliphatic group, R2 is an ethylene or propylene group and x, y and z 25 indicate that each of the groups -OR2- may be present, on average, more than once. Specific 25 examples of such triamines are those sold by Texaco under the trade designation "Jeffamine T" (R7=propylidyne, R2=isopropylene), e.g. Jeffamine T-403, Jeffamine T-300 and Jeffamine T-5000.

In addition to the ether amine, the amine component from which polyamides of the invention 30 are derived must contain an aliphatic diamine and this preferably an oc, w-diprimary aliphatic 30

diamine, especially a C2-C6 oc,<y-diprimary polymethylene diamine such as ethylene diamine or 1,6-hexamethylene diamene.

The ratio of ether amine to aliphatic diamine may vary widely depending on factors such as the molecular weight of the final polyamide and the nature and molecular weight of the ether 35 amine. In practice, however, it has been found that a molecular ratio of ether amine to aliphatic 35 diamine of from 0.05:1 to 2:1 is satisfactory, the preferred molar ratio of ether amine to aliphatic diamine being from 0.1:1 to 1:1.

The dicarboxylic acids used in the preparation of the polyamides of the invention are, in general, those usually used in the preparation of thixogenic polyamides. Preferred dicarboxylic 40 acids are the dimerised fatty acids or so-called "dimer acids" and aliphatic dicarboxylic acids in 40 which the carboxyl groups are separated by found or more carbon atoms such as adipic acid,

sebacic acid and azeleic acid. Aromatic acids such as isophthalic acid may also be used but in general they do not contribute towards the level of thixotropy obtained.

The amine component may contain a monoamine and/or the acid component may contain a 45 monocarboxylic acid in order to control the molecular weight of the final polyamide. As will be 45 appreciated, ether monoamines may serve as monoamine for this purpose but monofunctional aliphatic amines such as dodecylamine may also be used. Typical monocarboxylic acids which may be used for the control of molecular weight are saturated and unsaturated fatty acids and benzoic acids and its homologue.

50 The polyamide resins of the invention are prepared in a generally conventional manner, for 50

example by reacting the amine and acid components together at a temperature of from 200 to 260°C with removal of water of reaction. It is generally preferred that the reaction be carried out under conditions such that a random polyamide be obtained, i.e. reaction is carried out at relatively elevated temperature and/or the various components of the polyamide are added 55 together rather than sequentially which might result in the formation of a block-type copolyam- 55 ide. It is believed that if the polyamide is produced under conditions such that a block co-polyamide is prepared it may well be difficult to reproducibly produce the polyamide whereas by producing a random copolyamide reproducible levels of thixotropy are obtained.

The final polyamides suitably have acid values of up to 10 mgKOH/gm and amine values of up 60 to 10 mgKOH/gm. Generally the polyamide. Generally the polyamide will have a molecular weight 60 of from 1,000 to 20,000, those having lower molecular weights in this range being generally preferred.

The polyamide resins of the invention may be used to impart thixotropy to or thicken a wide variety of organic liquid materials, especially surface coating compositions comprising solutions, 65 in appropriate solvents, of, for example, drying and semi-drying oils, alkyd resins, urethane oils 65

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GB2190388A 3

and alkyds, oleresinous varnishes, acrylic resins, polyester resins and epoxy resins. In addition the polyamides of the invention can be used to impart thixotropy to a variety of aliphatic and aromatic hydrocarbon solvents and petroleum distillate fractions such as kerosene, gasolene,

lube oils, gas oils and fuel oils. It is noteworthy that, in the field of surface coating compo-5 sitions, the polyamides of the invention may be used to impart thixotropy not only to compositions containing white spirit as solvent but also to compositions containing white spirit as solvent but also to compositions thinned wth aromatic hydrocarbons such as xylol or mixtures of aromatic hydrocarbons and alcohols such xylokbutanol. Further the polyamides of the invention are capable of imparting thixotropy to materials which cannot be thickened by conventional 10 reaction with polyamides at elevated temperatures, such as thermoplastic and thermosetting acrylic resins and heat sensitive polyurethane oils and alkyds.

In general, the polyamide resins of the invention are used to impart thixotropy to a composition or solvent by adding the resin to the composition or solvent and dissolving it therein by simply warming, for example to a temperature of 80-100°C.

15 In order that the invention may be well understood the following examples are given by way of illustration only.

Example 1

Tall oil fatty acids (60g) dimer acid (224g), ethylene diamene (24g) and Jeffamine ED2201 20 (200g), were reacted under reflux for 1 hr and then heated to 230°C under conditions of distillation in 2hrs. The temperature was maintained at 230°C until no more water distilled off. The product was a solid slightly opaque resin; acid value (AV=4.3 mgKOH/g, Amine Value (Am.V)=5.5 mgKOH/g.

25 Example 2

The resin of Example 1 was reacted for a further 3hrs at 230°C. The product had an Av of 3.2 and an am.V of 4.5 mgKOH/g.

Example 3

30 A polyamide was prepared as described in Example 1 using a mixture of dimer acid (160g) and sebacic acid (20g) as acid components. The solid resin had an Av of 4.7 and an Am.V of 3.9.

Example 4

35 A polyamide was prepared as described in Example 1 except that the tall oil fatty acids were replaced by an equal weight of stearic acid. The resultant solid resin had an Av of 5.1 and an Am.V of 3.5.

Example 5

40 Tall oil fatty acids (126g), dimer acid (252g), ethylene diamine (27g) and Jeffamine T403 (68g) were reacted together under the conditions described in Example 1. The product was a soft/-tacky clear resin; AV of 5.7, Am.V of 4.3.

Example 6

45 Tall oil fatty acids (112g), dimer acid (224g), ethylene diamine (24g) and Jeffamine ED600 (120g) were reacted at 240°C for 3hrs. The resultant resin had an AV of 4.6 and an Am.V of 3.1.

Example 7

50 Dimer acid (336g), ethylene diamine (24g) and 3-stearyl oxypropylamine (131 g) were reacted together at 250°C for 3hrs. The product was a soft slightly tacky resin and had an AV of 3.9 and an am.V of 3.4.

Example 8

55 Tall oil fatty acids (112g), dimer acid (224g), ethylene diamine (24g) and bis(3 amino propyl)-polytetrahydrofuran (150g) were reacted together at 240°C fr 4hrs. The resultant clear soft resin obtained had an AV of 4.6 and an Am.V of 3.7.

Example 9

60 The procedure of Example 1 was repeated using Jeffamine D2000 (210g) in place of Jeffamine ED2001. The resultant resin was softer than that of Example 1 and had an Av of 4.3 and an Am.V of 4.0.

Example 10

65 Tall oil fatty acids (42g), dimer acid (168g), ethylene diamine (18g) and Jeffamine T5000

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GB 2 190 388A 4

(285g) were reacted together at 240°C for 4hrs. The product had an Av of 6.2 and an Am.V of 2.7.

Example 11

5 Dimer acid (370g), ethylene diamine (26.4g) and 3-ethoxy propylamine (45.3g) were reacted 5 together at 240°C for 3hrs. The resultant clear soft tacky resin had an AV of 4.2 and an Am.V of 3.1.

Example 12

10 The product of Example 1 was repeated using hexamethylene diamine (46.4g) in place of 10

ethylene diamine. The resultant solid resin had an AV of 2.6 and an Am.V of 3.1.

Example 13

Tall oil fatty acids (67g). Jeffamine ED600 (225g), ethylene diamine (11 g) and sebacic acid 15 (96.5g) were reacted together at 250°C for 3hrs. The product was a soft waxy solid; AV=4.6 15 mgKOH/g, Am.V=5.2 mgKOH/g.

The polyamide resins of Examples 1-13 were tested for thixotropic effect in a variety of vehicles and solvents. In the case of the vehicles, 5% by weight of the polyamide (on resin solids) was dissolved into the vehicle by warming to 80°C and then allowing to stand overnight 20 at ambient temperature. A 5% level was also employed for test with the solvents alone. 20

The results are shown in the following table.

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01

Ex. No.

VEHICLE

SOLVENT

NON-VOLATILE %

PRODUCT

1 & 2

65% oil length Soya-penta alkyd

White Spirit

60

Clear & similar gels

>1

55% O.L. linseed epoxy ester ii

60

It tl

65% O.L. Soya Urethane alkyd ii

55

tl

If

65% O.L. Soya Urethane oil ii

60

II

It

Hydroxy functional acrylic resin

Xylol

55

Clear gel

II

lOOpoise linseed stand oil

-

100

If

3

45% O.L. llnoleic-glycerol alkyd

Xylol

50

tt

It

40% O.L. linoleic-mixed polyol alkyd

4:1 Xylol:butanol

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It

4

65% O.L. Soya-penta alkyd

White Spirit

60

II

ft

45% O.L. Linoleic-glycerol alkyd

Xylol

50

tl tl

Saturated polyester resin

3:1 Xylol:butanol

80

It

5-12

65% O.L. Soya-penta alkyd

White Spirit

60

Clear gels

13

40.% O.L. Linoleic-mixed polyol alkyd

4 :1 Xylol:butanol

60

Clear weak gel

9

-

White Spirit

0

hazy weak gel ii

-

Xylol

0

Clear gel it

—

Petrol

0

Clear gel o

CO to

CD O to 00

00 >

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GB2 190388A

Paint Based on Patent Example

5% (on resin solids) of the thixogen of Example 1 was dissolved in a long oil soya-penta alkyd of a type used widely for the production of decorative products.

Alkyd properties were as follows:-

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Oil length % Non volatile % Solvent

Viscosity (c.stoke.) Hydroxy! value mgKOH/g

- 65

- White spirit

- 3,000-4,000

- 60

On cooling overnight the products formed a star bright gel. A white gloss paint was made to the following formulation

Thixotropic alkyd Rutile titanium dioxide White spirit G.P. driers

Methyl ethyl ketoxime (10%)

193.24 100.00 51.11 6.6

parts by weight parts by weight parts by weight parts by weight

6.6 parts by weight

A mill base was made using a pigment:binder ratio of 4:1. After 10 minutes high speed shear the remaining resin was added and the paint thinned to 3 poise with white spirit. The properties of the paint were compared with a commercial dripless type of paint made from the same alkyd (70pts) and a concentrated thixotropic alkyd (30pts) made according to the prior art high temperature process and was found to be completely acceptable. The two paints had the following properties:

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Viscosity (poise) Paint Solids (%) Flow

35 Gloss % 20760°

Paint using thixogen of Ex. 3.0 65.3 Excellent 79/88

Commercial Paint 3.0 62.1

Moderate 81/90

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Claims

1. A polyamide derived from:

40 (a) an amine component comprising: 40

(i) an aliphatic diamine;

(ii) an ether monoamine, an ether diamine or an ether triamine; and, optionally,

(iii) a monoamine other than an ether monoamine; and (b) an acid component comprising:

45 (iv) an organic dicarboxylic acid; and, optionally, 45

(v) an organic monocarboxylic acid.

2. A polyamide as claimed in claim 1 in which the molar ratios of ether amine (ii) to aliphatic diamine (i) is from 0.05:1 to 2:1.

3. A polyamide as claimed in claim 1 or claim 2 in which the ether amine (ii) is a polyoxyal-

50 kylene diamine or a polyoxyalkene triamine.

4. A polyamide as claimed in any one of the preceding claims in which the aliphatic diamine is a C2-C6 x,&i-polymethylene diamine.

5. A polyamide as claimed in claim 1 substantially as hereinbefore described with reference to the examples.

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6. A thixotropic composition comprising a polyamide as claimed in any one of the preceding claims dissolved in an organic solvent.

7. A thixotropic composition as claimed in claim 6 also containing a film-forming resin dissolved in the organic solvent.

8. A thixotropic composition as claimed in claim 6 substantially as hereinbefore described

60 with reference to the Examples.

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Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon) Ltd, Dd 8991685, 1987.

Published at The Patent Office, 25 Southampton Buildings, London, WC2A 1AY, from which copies may be obtained.