Sponged leather

SPONGED LEATHER 4.2.6.1 Formulation proposed by raw material supplier Calendered sponged leather. [Data from Mark K 136 Technical data sheet Crompton. June 1999.] ... 

Calendered sponged leather. [Data from Mark K136. Technical data sheet. 

Mark K 136 in combination with zinc oxide and barium stearate stabilizes the formulation and acts as a kicker, giving a very fine homogeneous eell structure. Produetion of sponge leather is a two stage proeess in which calendering is done at 155-180°C and foaming takes place in a heating ehannel at 200-230°C. 

Other stabilizers include special zincs for plasticized applications such as cable and organics added to calcium/zinc or used for pipe extrusion and co-stabilizers for metal soap and tin, improving long-term heat stability. Kickers (liquid barium/zinc and potassium/zinc) are PVC stabilizers that catalyse the decomposition of a blowing agent to be effective at lower temperatures, and can be used for sponge leather calendering. Epoxidized compounds are effective co-stabilizers in most systems chelators with metal soap improve heat stability. 

Sponge leather modifier Acrylic acid Steryl methacrylate... 

Sintering has been used to produce a porous polytetrafluoroethylene (16). Cellulose sponges are the most familiar cellular polymers produced by the leaching process (123). Sodium sulfate crystals are dispersed in the viscose symp and subsequently leached out. Polyethylene (124) or poly(vinyl chloride) can also be produced in cellular form by the leaching process. The artificial leather-tike materials used for shoe uppers are rendered porous by extraction of salts (125) or by designing the polymers in such a way that they precipitate as a gel with many holes (126). 

Usual adherends Natural rubber, masonite, wood, felt, fabric, paper, metal Rubber, sponge rubber, fabric, leather, wood, metal, painted metal, building materials Rubber, metals Plastic film, rubber, metal foil, paper... 

Rubber, sponge rubber, fabric, leather, wood, metal, painted metal, building materials Rubber, metals... 

The TVOC value of a sample is determined by the integration of the chromatographic peak area between C6 and C16 with 100 ng total integrated area toluene peak comparison calculated. The two standards hexane and w-hexadecane determine the retention time position of the C6 and C16 peak (see Figure 4.158). For the test samples the peak area between the calibrated retention times of n-hexane and n-hexadecane is determined as a total peak area. Representative chromatograms of a leather and a sponge sample are shown with the total ion current in Figures 4.159 and 4.160. 

The fur treated in this manner, on the flesh side has the appearance of a fresh skin if it isdesired to impart to it the appearance of tawed leather, this can be accomplished in a very simple manner by spreading over it a cold solution of alum or aluminium sulphate, leaving it to dry and then dabbing it over with a sponge dipped in ammonia. In this way the aluminium hydroxide is separated from the flesh side of the skin, which thereby has the appearance of tawed leather. 

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