RRIM

When surfactant-coated glass fibers are included to improve product flexibility and reduce thermal expansion, these semibatch processes are termed reinforced reaction injection mol ding (RRIM). 

Special producer limits and related controls are also imposed by the Rubber Research Institute of Malaysia (RRIM) to provide an additional safeguard. 

RBIM Training Manual on Tapping Tapping Systems andYield Stimulation ofHevea, RRIM, Kuala Lumpur, Malaysia, 1980. 

The largest segment of the CASE family of polyurethanes are elastomers. Cast polyurethane elastomers reached a new dimension when high pressure impingement mixing led to reaction injection molding (RIM). This technology is used widely in the automotive industry, and reinforced versions (RRIM) and stmctural molded parts (SRIM) have been added in more recent years. 

The reinforced reaction injection moulding (RRIM) process is a development of RIM in which reinforcing fillers such as glass fibres are incorporated into the polymer. One advantage of such a system is to reduce the coefficient of thermal expansion, and with a 40-50% glass fibre content the coefficient is brought into line with those of metals. 

For RRIM-based composites, the main benefit is the case with which the properties can be varied across a wide range. Decorative finishes can be applied to RRIM molding by painting or, where color matching between components is less important, by self-coloring. However, color coating of the mold surface prior to RIM provides a better finish. 

Different materials can be used such as nylon, polyester (TS), and epoxy, but TS polyurethane (PUR) is predominantly used. Almost no other plastic has the range of properties of PUR. Modulus of elasticity range in bending is 200 to 1,400 MPa (29,000-203,000 psi) and heat resistance from 90 to over 200°C (122-392°F). The higher values are for chopped glass-fiber-reinforced RIM (RRIM). 

In the reinforced RIM (RRIM) process a dry reinforcement preform is placed in a closed mold. Next a reactive plastic system is mixed under high pressure in a specially designed mixing head. Upon mixing, the reacting liquid flows at low pressure through a runner system to fill the mold cavity, impregnating the reinforcement in the process. Once the mold cavity is filled, the plastic quickly completes its reaction. The complete cycle time required to produce a molded thick product can be as little as one minute. 

The advantages of RRIM are similar to those listed for RTM. However, RRIM uses preforms that are less complex in construction and lower in reinforcement content than... 

Reimer-Tiemann reaction, 6 236 of salicylic acid, 22 5 Reinforced composites flax fiber in, 22 594 silylating agents and, 22 701-703 Reinforced plastics, 26 750-751 asbestos applications, 3 311 Reinforced polyester composites, 20 114 Reinforced reaction injection molding (RRIM), 25 456 Reinforcement... 

Here 01, a2, b and b2 are real coefficients while rriM is complex. From the last two terms, representing a Majorana mass term for the quarks, we see that the massless degrees of freedom are the ipa=3,i- The latter possesses the correct quantum numbers to match the t Hooft anomaly conditions [32],... 

To quantitatively characterize the surface roughness of the Pt films, the rms roughness cr of the electrodes was evaluated and the resulting values are indicated in Figures 10a, 10b and 10c, respectively. From the comparison between height fluctuation of all the film... 

Low-pressure injection moulding, RIM, RRIM for liquid polyamide ... 

Low-pressure inj ection moulding, RIM, RRIM o are suited for medium output... 

RRIM - reinforced reaction injection moulding - the resin is reinforced with short fibres... 

The main advantages and drawbacks of the low-pressure RIM or RRIM processes are ... 

Other ingredients include catalysts to control/balance the polymerization/cure reactions, surfactants for foam uniformity, fillers for stiffening, pigments for coloration, flame-retardants where needed, and especially short glass reinforcing fibers to increase strength and dimensional stability in Reinforced RIM (RRIM). 

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... 

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