Milled glass

Steel Plants Electric Arc Furnaces and Argon-Oxygen Decarhurization Vessels Constructed after August 7, 1983 Kraft Pulp Mills Glass Manufacturing Plants Grain Elevators... 

Particulate Ductility, Ductility, milled glass or glass beads... 

Chopped or milled glass fibres 0.1-20 mm length, 5-25 [rm in diameter, aspect ratio from 4 to 4000. These fibres are dispersed into the polymers. 

Reinforced RIM (RRIM) elastomers are used. By the addition of reinforcing fillers such as milled glass fiber, glass flake, or mineral fillers in the polyurethane or short to long glass fiber in preforms, fabric, or mat forms placed in the mold cavity, the properties of the material can be altered to meet high performance requirements of the part (Chapter 15). The reinforced elastomers are used to increase flexural modulus, improve thermal properties, and improve dimensional stability.267... 

Fillers. Fillers mentioned for epoxy systems (subsection 2.2.6.4) are used in polyurethanes too. Ground calcium carbonate (coated as well as uncoated) is commonly used. Barium sulphate, silica fumes, wood flour and milled glass fibres are also used. 

The former material was evaluated with and without Owens/Coming Fiberglas 737 milled glass whUe the latter resin was always shot neat, but evaluated with and without Owens/Coming Fiberglas M-8610 random mat in the tool. The stmctural polyol blend had a viscosity of about 1,780 centistokes at 77°F, and an extended gel time of about 15 seconds at the mold temperature of 140"F and component temperature of 100 F. The isocyanate had a viscosity of 200 cps at the same temperature. The A/B ratio was about 1 1. 

Table XI demonstrates the effect of fiber length on properties for a type of RIM processable material - the urethane modified isocyanurate which has low impact. Table XI ccnpares milled glass fibers with 1/8" chapped strand. The longer aspect length chopped strand provides for true reinforcement. However, it cannot be used in current RRIM equipment.

For hammer-milled glass (HMG), the bulk volume can be determined by direct measurement in air, and data for HMG of different aspect ratios have been published by Milewski (2) and by Isham (3). 

Many RIM formulated systems also incorporate milled glass fibers, or other kinds of fillers to bring about a reduction in linear thermal expansion and contraction, and increase part rigidity. 

Table III. Effect of IMR Plus Milled Glass Fiber Reinforcement on...

AA Owens Corning 1/16" parallel to flow. milled glass properties of RRIM... 

Likewise, when formulation C was also modified by 10% milled glass fiber, the toughness of the polymer remained Intact, as evidenced by low loss of elongation and retention of tear strength - a good measure of retained bond strength. These results are also shown In "Table HI". 

Reinforced RIM urethane using milled glass fibers (1/16 ) at 25% loading or more is now the "state of the art" reinforcement. 

Flexural Modulus. Figure 5 shows flex modulus values at 23 °C measured parallel and perpendicular to flow. The nonreinforced urethane polymer has a value of about 50,000 psi. Columns B and C show the results obtained with 8.5% and 20% loadings of milled glass fibers, respectively. Column D shows results obtained with 3.5% loadings of 1/8 chopped Integral strands. The flex modulus increased by about 20%. Column E shows data for 13.4% integral chopped strands the increase was more than 240% of the original... 

Impact Strength. Figure 6, notched Izod impact strength, shows one of the main reasons for the interest in chopped integral strands (c/s) as RRIM urethane reinforcement. The nonreinforced urethane polymer used in this study had an impact value of approximately 12 ft-lb/in. Reinforcement with 20% milled glass fibers lowers this value to about 5 ft-lb/in. (Column B). 

Tensile Strength. Tensile strength data (Figure 7) indicate that the highest value was obtained with milled glass fiber (20% loading) and the relatively low value obtained with chopped integral strands. This may be related to the aspect ratio of dispersed milled fiber in the composite compared to chopped... 

The pneumatic conveyors are suitable for refuse-derived fuel, dense and light plastics, granulated paper, milled glass, and chip wood/timber. They are not suitable for mixed municipal solid waste due to the variable characteristics of the components, organics/putrescibles due to odors, and material deposition in the rotary valves, and metal objects, except shredded aluminum. 

The materials shown in Table I are available in varying molecular weights and filler compositions. For molded circuit applications, the most commonly used fillers comprise chopped or milled glass fibers and/or mineral talcs. In addition to these fillers, additional components may be incorporated to impart flammability resistance or to promote electroless plating. The latter is achieved by the addition of a proprietary mineral filler which renders the polymer "catalytic" to plating. 

This process, in which a high modulus urethane elastomer is reinforced by milled glass fibers is currently commercially used in a three piece air spoiler used on the 1980 Pontiac Sunbird. The first use of reinforced RIM urethane front fenders is scheduled for use on a 1981 model car. 

Studies of the effects of various types of fiber and particulate fillers have shown that milled glass fibers are in the near term the most suitable means to achieve part stiffness and the required reduction in the coefficient of linear thermal expansion to allow practical mating of RIM polyurethane panels with steel. 

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