Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2001-03-26
2003-03-04
Hampton-Hightower, P. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C525S420000, C525S422000, C525S425000, C525S432000, C525S434000, C525S455000, C526S935000, C156S166000, C156S180000
Reexamination Certificate
active
06528615
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates more particularly to copolymers containing polyamide blocks and polyether blocks based on ethoxylated primary amines, these copolymers having a melting point of between 80° C. and 135° C. Copolymers containing polyamide blocks and polyether blocks are generally obtained from the condensation of polyamide blocks containing carboxylic acid ends with polyetherdiols. Ethoxylated primary amines constitute a particular class of polyetherdiols.
These copolymers containing polyamide blocks and polyether blocks are useful as adhesives of the HMA (or hot melt adhesive) type, i.e. they are deposited in molten form onto the surfaces to be bonded and adhesion is then obtained when they return to the solid state by cooling. These adhesives are useful in the textile industry.
PRIOR ART
Patent EP 281 461 describes copolymers containing polyamide blocks and polyether blocks based on ethoxylated primary amines. The polyamide blocks are made of either nylon-6, nylon-6,6, nylon-11 or nylon-12 and the melting points are between 145° C. and 202° C. The description mentions that these copolymers have good water resistance when compared with copolymers containing polyamide blocks and polyether blocks but whose polyether blocks are of polyethylene glycol (PEG). No mention is made of their use as hot melt adhesives; only their mechanical properties are described.
Patent WO 99/33659 describes copolymers containing polyamide blocks and polyether blocks consisting of PEG, these copolymers having a melting point of about 110° C. to 125° C. The polyamide blocks consist of sequences based on diamines, diacids and lactams or &agr;,&ohgr;-aminocarboxylic acids. These copolymers can be used as hot-melt adhesives in breathable structures, i.e. structures that are permeable to water vapour but impermeable to liquid water.
U.S. Pat. No. 5,489,667 describes copolymers containing polyamide blocks and polyether blocks consisting of PEG or PTMG (polytetramethylene glycol), these copolymers having a melting point of about 110° C. to 125° C. These copolymers can be used, in unmodified form, as hot-melt adhesives, or can first be extruded into fibres in the form of a nonwoven and this nonwoven can then be placed between two fabrics which it is desired to bond together, the bonding being obtained by heating and pressing. The copolymers described in this prior art have good resistance to washing with detergents in aqueous phase, but withstand hot ironing less well, in particular steam ironing.
THE TECHNICAL PROBLEM
Attempts have been made to use the copolymers described in the second prior art to bond pieces of different textiles constituting an item of clothing, but the resistance to dry-cleaning products and to the usual detergents in aqueous solution is not perfect. The melting point of the copolymers described in the first prior art is too high for them to be used as hot melt adhesives in the textile industry.
Thus, there is a need to develop products with a melting point which is compatible with their use as hot melt adhesives, i.e. products melting approximately between 80° C. and 135° C. These products also need to withstand dry-cleaning products, as well as the usual detergents in aqueous solution and treatment with steam during ironing.
SUMMARY OF THE INVENTION
The present invention relates to copolymers containing polyamide blocks and polyether blocks based on ethoxylated primary amines, these copolymers having a melting point of between 80° C. and 135° C. and an MFI (melt flow index) of between 5 and 80 g/10 min (2.16 kg-150° C.). The melting point is measured by DSC (differential scanning calorimetry) or according to DIN 53736, Volume B (visuelle Bestimmung der Schmelztemperatur von teilkristallinen Kunststoffen) optically using a heating bench and a microscope.
The present invention also relates to adhesives of the HMA type (or hot melt adhesives) consisting of the above polymers containing polyamide blocks and polyether blocks.
The copolymers containing polyamide blocks and polyether blocks result from the copolycondensation of polyamide sequences containing reactive ends with polyether sequences containing reactive ends, such as polyamide sequences containing dicarboxylic chain ends with polyetherdiols, the products obtained in this particular case being polyetheresteramides.
The polyamide sequences containing dicarboxylic chain ends are obtained, for example, from the condensation of &agr;,&ohgr;-aminocarboxylic acids, lactams or dicarboxylic acids and diamines in the presence of a chain-limiting dicarboxylic acid.
The number-average molar mass {overscore (M)}n of the polyamide sequences is between 300 and 15,000 and preferably between 600 and 5000. The mass {overscore (M)}n of the polyether sequences is between 100 and 6000 and preferably between 200 and 3000.
The copolymers containing polyamide blocks and polyether blocks can also comprise randomly distributed units. These copolymers can be prepared by simultaneously reacting the polyether and the polyamide block precursors.
For example, a polyetherdiol, a lactam (or an &agr;,&ohgr;-amino acid) and a chain-limiting diacid can be reacted together in the presence of a small amount of water. A polymer essentially containing polyether blocks, polyamide blocks of very variable length, but also the various reagents which have reacted randomly and which are randomly distributed along the polymer chain, is obtained.
According to a first form of the invention, the polyamide sequences result, for example, from the condensation of one or more &agr;,&ohgr;-aminocarboxylic acids and/or from one or more lactams containing from 6 to 12 carbon atoms in the presence of a dicarboxylic acid containing from 4 to 12 carbon atoms, and have a low mass, i.e. {overscore (M)}n from 400 to 1000, advantageously from 400 to 800. Examples of &agr;,&ohgr;-aminocarboxylic acids which may be mentioned are aminoundecanoic acid and aminododecanoic acid. Examples of dicarboxylic acids which may be mentioned are adipic acid, sebacic acid, azelaic acid, isophthalic acid, butanedioic acid, 1,4-cyclohexyldicarboxylic acid, terephthalic acid, the sodium or lithium salt of sulphoisophthalic acid, dimerized fatty acids (these dimerized fatty acids having a dimer content of at least 98% and being preferably hydrogenated) and dodecanedioic acid HOOC—(CH
2
)
10
—COOH.
Examples of lactams which may be mentioned are caprolactam and lauryllactam. Caprolactam will be avoided, unless the polyamide is purified of the monomeric caprolactam remaining dissolved therein.
Polyamide sequences obtained by condensing lauryllactam in the presence of adipic acid or dodecanedioic acid and having a mass {overscore (M)}n of 750 have a melting point of 127-130° C.
According to a second form of the invention, the polyamide sequences result from the condensation of at least one &agr;,&ohgr;-aminocarboxylic acid (or a lactam), at least one diamine and at least one dicarboxylic acid. The &agr;,&ohgr;-aminocarboxylic acid, the lactam and the dicarboxylic acid can be chosen from those mentioned above.
The diamine can be an aliphatic diamine containing from 6 to 12 carbon atoms, and can be an arylic and/or saturated cyclic diamine.
Examples which may be mentioned are hexamethylenediamine, piperazine, tetramethylenediamine, octamethylenediamine, decamethylenediamine, dodecamethylenediamine, 1,5-diaminohexane, 2,2,4-trimethyl-1,6-diaminohexane, polyoldiamines, isophoronediamine (IPD), methylpenta-methylenediamine (MPDM), bis(aminocyclohexyl)methane (BACM), and bis(3-methyl-4-aminocyclohexyl)methane (BMACM).
The various constituents of the polyamide sequence and their proportion are chosen so as to obtain a melting point of between 80° C. and 135° C. and advantageously between 100° C. and 130° C..
Copolyamides with a low melting point are described in U.S. Pat. No. 4,483,975, DE 3 730 504 and U.S. Pat. No. 5,459,230; the same proportions of constituents for the polyamide blocks are used in the second form of the invention. The polyamide blocks of the second form can also be th
Hilgers Hermann
Linemann Reinhard
Atofina
Hampton-Hightower P.
Millen White Zelano & Branigan P.C.
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