CA1120193A

CA1120193A - Polyamides

Info

Publication number: CA1120193A
Application number: CA000298408A
Authority: CA
Inventors: Adrien G. Hinze; Hendrik G. Stigter
Original assignee: Emery Oleochemicals LLC
Current assignee: Emery Oleochemicals LLC
Priority date: 1977-03-07
Filing date: 1978-03-07
Publication date: 1982-03-16
Also published as: NL7802494A; IT7820908A0; DE2809769A1; FR2383209A1; IT1094186B; NL164582C; ES467591A1; NL164582B

Abstract

ABSTRACT OF THE DISCLOSURE

Novel polyamides are provided herein which are suitable as hot-melt adhesives. The polyamids contain groups derived from a polymeric fatty acid containing 70 - 99% by weight of dinner acid and from 90 - 110 mole percent of an amine component cioonsisting essentially of 10 - 100 mole percent trialone of the structure

Description

11;~0~93 The invention relates to polyamides and their preparation, which polyamides are suitable for use as hot-melt adhesives, shaped arti-cles consisting completely or partly of such a polyamide, as well as to a method for the manufacture of articles bonded with such a polyamide and to the articles so obtained.
Polyamides which are suitable for use as hot-melt adhesives are known. These polysmides must meet a number of requirements concerning adhesion, toughness, melting point, viscosity, elongation, elasticity, tensile strength, etc. In order to obtain favourable properties with respect to elongation and tensile strength highly viscous polyamides have been developed which are linear or almost completely linear. Such linear polyamides are obtained by reacting molecular-distilled polymeric fatty acids consisting of 80-99% by weight of dimer and of which the amount of trimer and higher oligomers is approximately compensated by the amount of monomer, together with at least one bifunctional amine. Sometimes another, lower dicarboxylic acid is also incorporated.
Polyamides with`-improved peeling strength are obtained by in-corporating not only ethylenediamine ~EDA) but also another polyamine e.g., diethylenetriamine (DETA) but also another polyamine e.g., diethyl-enetriamine (DETA) and/or hexamethylenediamine (HMDA) in the reactionmixture. It has been found that DETA-based polyamides have particularly high peeling strengths. However, propably due to the trifunctionality of DETA, polyamides based thereon are brittle and lack properties, e.g., elongation. If, however, another X - 2 _ 0~93 diamine like, e.g., HMDA, is present, elongation is quite satis~actory but the peeling strength is unsntisfactory when compared with DETA-based poly-amides.
Polyamides exhibiting elongation are usua11y obtained from poly-meric fatty acids with a higher dimer content exceeding 80 or even 85% of dimer. Also a certain relationship between the percentages of monomeric and trimeric constituents must be satisfied. Such pure dimers can only be obtained on a practical scale by molecular distillation of the dimer, which is cumbersome and adds considerably to the cost of the products obtained.
Therefore, an object of one broad aspect of this invention is to provide polyamides combining toughness and elongation on the one hand with a high peeling strength on the other hand.
An object of another aspect of this invention is to provide non-brittle polyamides which are based on normal technical grades of polymeric fatty acids containing 75 - 85% of dimer acid.
According to a broad aspect of the present invention, polyamides are provided combining excellent elongation with high peeling strength, which are suitable for use as hot-melt adhesives, the polyamides being comprised of groups derived from polymeric fatty acid containing 70 - 99%
by weight of dimer acid and 90 - 110 mole percent of an amine componen~
consisting essentially of 10 - 100 mole percent triamine of the structure H~N - R2 ~ N - R3 H2 Rl ~
wherein Rl is an alkyl group having from 1 - 3 carbon atoms and R2 and R3 are the same or different bivalent hydrocarbon radicals together containing from 4 up to 24 carbon atoms, the polyamide having an acid value less than 15 and amine value between 10 and 125.
Very suitable amines according to variants of this invention are, . .. ..

e.g., bis-(3-aminopropyl)-mcthylflmine~ bis-(3-aminol-ropyl)-etlly]allline i~nd other homologues thereof. Furtllermore, by other variants of this LnventLon, R2 and R3 are preferably alkyl groups and contain 2 to 6, preferably 2 to 4, carbon a~oms.
By another variant of this invention, R2 and R3 of the triamine represent C2-C4 alkylene groups.
By another variant, the polymeric fatty acid contains 75 - 80%
by weight of dimer.
By yet another variant, the triamine is combined with C2-C20 diamine in a mole percentage ranging from 10 - 100:0 - 90.
By still another variant, the C2-C20 diamine contains two primary amine groups removed from each other by less than 10 carbon atoms.
By a still further variant, the polymeric fatty acid is combined with a dicarboxylic acid containing 2 - 12 carbon atoms, constituting from 0 - 60 mol% of the total carboxylic acid constituent.
These polyamides can be obtained according to another aspect of this invention by a process which comprises reacting a polymeric acid or lower alkyl ester thereof containing 70 - 99% of dimer with 90 - 110 mole percent of an amine component consisting essentially of 10 - 100 mole percent of a triamine or salt thereof of the structure H2N R2 1 R3 NH2, in which Rl is an alkyl group containing from 1 -3 carbon atoms and R2 and R3 are the same or different bivalent hydrocarbon radicals together containing 4 - 24 carbon atoms.

B

11;~0193 The C2-C20 dlamine, optionally used according to a varlant of this process should contain two primary amine groups which are removed from each other by not more than 10 carbon atoms. Preferably by one variant the diamine contains 2-12 carbon atoms. Very suitable amines according to another variant are ethylene diamine, propylenediamine and hexamethylenediamine.
The amine constituent used consists preferably of 0-90 mol% of the diamine and 10-100 mol% of the triamine indicated above. Instead of the amines it is also possible by other variants to use a corresponding salt or another functional derivative as far as it can still be -amidated.
If desired by still another variant, another dicarboxylic acid that may contain from 2-12, preferably 6-9 carbon atoms can be built into the polyamide. Suitable dicarboxylic acids are e.g. adipic acid, azelaic acid, sebacic acid, dodencanedicarboxylic acid and terephthalic acid. These acids or their lower (Cl-C4) alkyl esters can be included in the reaction mixture in amounts of up to 60 mol% of the acid componen~. The precise amount of this dicarboxylic acid depends on the nature of the dicarboxylic acid and the rise in melting point of the polyamides that is desired. The same applies for monocarboxylic acid, usually C2-Clg, which may be present according to another variant in from 10 percent by weight of the total acid constituent.
On the one hand by a variant of this invention, the amount of polymeric acid and possibly other dicarboxylic acid or esters thereof to be used and, on the other hand, the amount of amine component are such that 90-110 mol% of amine or salts thereof, based on the polymeric fatty acid (calculated as dimeric fatty acid), and possibly of other dicarboxy-lic acid or monocarboxylic acids are present, so that roughly equivalent amounts of primary amine groups and carboxylic groups are present. Typi-cally the polyamide obtained shows an acid value below 15, preferably be-_ 5 _ 11;~0193 low 10 and an amine value above 10 but below 125, preferAbly above 20 butbelow 100, and even below 40.
Furthermore by yet another variant, a small amount of C5-C12 lactam can also be built as an extender into the polyamide. Such lactams are e.g.

- 5 a ---- llZOi93 caprolactam and laurlnlactam. The amount of lactam is les~ than 40% by weight baset on the dlmer, preferably less than 25% by weight.
The polymeric fatty acid used in one variant of thi~ invention is generally obtained by catalytic polymerisation of mono- and poly-unsatura-ted fatty acits predominantly containing 18 carbon atoms. This result~ in a yield of up to 60% by weight of polymerized fatty acids being obtained.
The catalyst is removed by filtration, after which the unconverted monomer-ic fraction is stripped off under reduced pressure. Sometimes it i8 de-sirable, in connection with the stability or colour, to hydrogenate the polymeric fatty acid residue to an iodine value below 20 or even below 10.
Polymeric fatty acids of these types are on the market under the registered Trade Mark of "Empol" of Emery Industries, Cincinnati, Ohio.
An embodiment of the present invention is that these raw poly-, meric fatty acids, containing 75% of dimer, can be built into polyamides which are particularly suitable as hot-melt adhesives. Up to now for that purpose particularly dimeric fatty acids of greater purity have been used which furthermore had to meet special requirements concerning the content of trimer and higher oligomers with respect to the content of monomers.
' Such pure dimers, which contain more than 83% and generally more than 90%
of dimer, can only be obtained on a practical scale by molecular distil-lation, which is cumbersome and costly.
It is quite unexpected that, on the basis of technical grade polymeric fatty acids, flexible polyamides can be obtained having good elongation, which are tough and of which the peeling strength from metal (steel) is exceptionally high. Polyamides satisfying these requirements are particularly suitable for use as hot-melt adhesives for metals, wood, paper and textiles.
The preparation of the polyamides takes place by known pro-cedures, namely by heating the reactants to a temperature of 180-300C, ~1~ --6--11;~0193 sometimes under a nltrogen atmosphere. The volatile product~ developlng, e.g. water or lower alcohol, can be distilled off, optionally azeotropi-cally when an entrailment agent hag been added. Often, at the end of the reaction, heating is carried 6 a -11~0193 out under reduced pressure. The polyamlde obtained i8 generally cast into moulded articles, e.g., blocks, bars, granules, flskes or films and the like. The solid polyamide i8 suitable in this form for use as a hot-melt adhesive, but sometimes other ingredients, e.g., oxldation stabilizers, are added.
The invention also provides by another aspect, a method for bonding substrate parts together, for which it is also important that the melting point should not be too low and its melt viscosity relatively high, as the adhesive should become firm quickly so that the parts to be bonded only have to be pressed together for generally less than half a minute.
This requirement ~is also met by the polyamides according to aspects of the present invention.
The invention will now be further explained by means of the following examples:
Examples 1-7 In these experiments polyamides were prepared by reacting equivalent amounts of acid and reactive amine for two hours at 200C and finally heating for two hours under a pressure of 15-20 mm Hg at 230C.
The compositions and properties are apparent from the Table 1 11;~0193 8 ~
P~
~ Z;
E~

~, u~ ~ O ~ a , ¢
O
rl U~
O O O O ~ ~ ~
D O
O /~

,~ O
~ V o O O O U~ O U~
V ~ ~ ~ ~ ~ ~ ~ ~ O ~
~ ~ ~ ~ ~ ~ ~ ~ ~ O
O ~ J~ ~

~ ~ C ~ ~ ~ 0 00 0 V
~ ~ . . O
¢ P ~1 ~ ~ ~1 ~ ~ ~ ~I E
O
O ~D ~ u~
¢ ~ ~ O O
H P- ~, g j~i ~ ~ I O U~ U~ o o o o ,1 ~o ~ o 0 ~ o ~1 H

o ulul O O O O ~ 3 ~ ~) c~ ~" lv ~1 ~ O O O u~ I~ O O
N C~
~ -v,a u ~ ~ ~ 3 ~ ~, ~d o oo u~ ~i o o ~î v V ol )I`I` o ~ ~ ~d X ~ ~

!, oo o o oo o ~ ~ ~ ~ ~ ~
O J~ X.. .... .. .. .. ..
.. ~ ~ ~
I~ r~r~ rl ~ O
O O ~0~ ~ ~ ~ 1~ O ~ 00 .

11;~0193 Example 8 In a manner as described above for Examples 1-7 polyamides were prepared as indicated below.
Comparison AComparlson B Example 8 Polymeric fatty acid (eq) 2.48 2.24 3.0 Oleic acid (eq) 0.075 0.14 Azelaic acid (eq) 1.12 1.33 1.59 Ethylene diamine (eq) 2.60 2;21 2.67 Diethylene triamine (eq) 2.23 10 Hexamethylene diamine (eq) 1.74 BAPMA (eq) 2.1 Mechanical properties:
Viscosity (PaS) 1.5 (160C) 5.7 (190C) -9.7 (190C) Softening point (C) ` 140 146 141 Elongation (%) 90 400 ~700 T peel (N/cm) 13.5 5 16 * Empol 1024 (the registered Trade ~ark of Emery Industries, Cincinnati, Ohio, containing <0.1% monomer, 80% dimer and 20% trimer) ** Empol 1010 (the registered Trade Mark of Emery Industries, containing < 0.1% monomer, 96% dimer and 4% trimer) *** BAPMA (e.g.~ denotes equivalents to primary amine groups only 11;~0193 Examples 9-11 In a manner as described above for Examples 1-7 polyamides were prepared and their properties were evaluated as indicated below.
Com Example 9 10 11 12 parison C
Polymeric fatty acids(eq) 3 1.96 1.79 3.0 2.28 ***
Azelaic acid (eq) 1.59 1.03 0.98 3.0 0.53 Isophthalic acid (eq) 0.23 BAPMA (eq) 2.1 1.37 1.36 3.74 EDA (eq) 2,67 1.75 2.48 2.3 HMDA (eq) 1.75 0.57 Stearic acid (eq) 0.18 Acid value 2.4 0.7 1.4 1.1 8.5 Amine value 58.5 62.9 55 77 2.6 Viscosity at 190C (PaS) 4.47 5.44 5.0 4.15 4.62 Softening point (B+R) 116.5C 116C 117C 148C 151C
Elongation (~)510 500 800 250 75 T-peel (N/cm) 14 13 14.5 17.5 6 Empol 1024 Empol 1010 Adipic acid.
**** BAPMA (e.g.) denotes equivalents to primary amine groups only

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A polyamide comprised of groups derived from a polymeric fatty acid containing 70% to 99% dimer acid and 90 - 110 mole percent of an amine component consisting essentially of 10 - 100 mole percent triamine of the structure wherein R1 is an alkyl group having from 1 - 3 carbon atoms and R2 and R3 are the same or different bivalent hydrocarbon radicals together containing from 4 up to 24 carbon atoms, said polyamide having an acid value less than 15 and amine value between 10 and 125.

2. Polyamide according to claim 1 in which R2 and R3 of the triamine represent C2-C4 alkylene groups.

3. Polyamide according to claim 1 in which R1 is a CH3-group.

4. Polyamide according to claims 1, 2 or 3 in which the polymeric fatty acid contains 75 - 80% by weight of dimer.

5. Polyamide according to claim 1 including up to 90 mole percent of a C2-20 diamine.

6. Polyamide according to claim 5 in which the C2-C20 diamine contains two primary amine groups removed from each other by less than 10 carbon atoms.

7. Polyamide according to claims 1 or 5 including up to 60 mole percent of the total carboxylic acid constituent of a dicarboxylic acid containing 2 - 12 carbon atoms.

8. A process for preparing a polyamide comprising reacting a polymeric acid or lower alkyl ester thereof containing 70 - 99% of dimer with 90 - 110 mole percent of an amine component consisting essentially of 10 - 100 mole percent of a triamine or salt thereof of the structure in which R1 is an alkyl group containing from 1 - 3 carbon atoms and R2 and R3 are the same or different bivalent hydrocarbon radicals together containing 4 - 24 carbon atoms.

9. A method for bonding substrate parts together comprising melting a polyamide as claimed in any one of claims 1, 2 or 5, applying it as a layer to at least one substrate part; covering it with another substrate part; and pressing the parts together for a short period of time.