Food or edible material: processes – compositions – and products – Inhibiting chemical or physical change of food by contact... – Treating liquid material
Patent
1996-09-20
1998-01-13
Edwards, Newton
Food or edible material: processes, compositions, and products
Inhibiting chemical or physical change of food by contact...
Treating liquid material
428395, D07G 300
Patent
active
057077339
DESCRIPTION:
BRIEF SUMMARY
The invention relates to dimensionally stable nylon-6,6 monofilaments having a linear density of 150 dtex for producing precision wovens.
Screen printing generally employs precision wovens composed of polyester (PET). The reason for this preference over polyamide is the distinctly higher modulus and the lower relaxation, i.e. lower tension loss of tensioned screens, of PET. A high precision woven modulus means better consistency in the tensioning process and also a higher printing precision due to a higher return force. Low relaxation has a positive effect on printing screen life.
The situation is different in direct tile printing. This sector employs pigment dyes which are very abrasive. It is known that the resistance to these dyes of polyamide precision wovens is distinctly higher than that of polyester precision wovens, so that the specific advantages and disadvantages of polyester and polyamide are roughly in balance. For this reason, polyamide is frequently used in direct tile printing as well as polyester. Attempts at achieving decisive improvements in the modulus and relaxation characteristics of polyamide wovens in the direction of polyester wovens by optimizing the weaving step have already been tried (H. P. Lisson, Serigraphie/-Siebdruckpraxis 5/92, pages 36-43). The polyamide woven obtained does show certain improvements over the normal polyamide fabric, but these improvements are still insufficient as regards the modulus and the relaxation characteristics of the monofilaments.
It is an object of the invention to provide a monofilament which has a distinctly higher modulus than the standard polyamide filament.
It is the further object to improve the relaxation or tension loss in an aqueous medium so as to achieve at least the level of polyester.
It is a further object to provide monofilaments which make it possible to produce precision wovens, especially for direct tile and hollow body printing, with the desired properties without additional operation.
The object according to the invention is achieved when the monofilaments have a breaking strength of at least 60 cN/tex, a breaking extension of less than 25%, a specific LASE 2%, based on the original linear density, of at least 7.5 cN/tex, a specific LASE 5%, based on the original linear density, of at least 18 cN/tex, a specific LASE 10%, based on the original linear density, of at least 40 cN/tex, and a dry relaxation of less than 25%.
It is surprising that the monofilaments according to the invention are effective in producing a precision woven having an approximately 25% higher modulus (T10 value) and an approximately 50% improved relaxation characteristic compared with the prior art. The woven obtained is also notable for a very uniform appearance, and the likelihood of warp thread breakages in weaving is much reduced.
The retardation reflects the creep characteristics of a thermoplastic monofilament. A monofilament retardation of less than 8% is particularly advantageous. A retardation in the monofilament of more than 8% leads to insufficient dimensional stabilities in the finished fabric.
Methods of Measurement
The mechanical properties of the monofilaments were measured according to the standards DIN 53815 and DIN 53834.
The retardation (creep) of the filaments was measured by weighting a monofilament with a tension of 2.5 cN/dtex and then recording the lengthening as a function of time. The retardation is reported in percent of the original length after a retardation time of 120 minutes.
The relaxation of the filaments in the dry state was measured by weighting a monofilament with a tension of 2.5 cN/dtex and then recording the tension loss as a function of time. The relaxation is reported in percent of the original tension after a relaxation time of 60 minutes.
The wet relaxation of the monofilament is measured in line with the tensioning process and the subsequent use of a screen in actual screen printing. As with the tensioning of a woven on a stenter, the thread is first pulled and held for 10 minutes with a constant specific fo
REFERENCES:
patent: 4652488 (1987-03-01), Willemsen et al.
patent: 5405696 (1995-04-01), Cuculo et al.
patent: 5419964 (1995-05-01), Boles
Hans Peter Lisson, Ceranyl--das Siebdruckgewebe fuer die Fliesenindustrie, May 1992 (No Translation).
Kurt Max
Schaffner Paul
Edwards Newton
Rhone-Poulenc Viscosuisse SA
Striker Michael J.
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