摘要:
The crosslinker of the invention is an asymmetrical polyvinyl crosslinker that disassociates at elevated temperature, and is especially useful in the preparation of superabsorbent polymers.
摘要:
An olefin metathesis process involving contacting an unsaturated fatty acid ester or unsaturated fatty acid, such as methyloleate or oleic acid, with a lower olefin, preferably ethylene, in the presence of a metathesis catalyst so as to prepare a first product olefin, preferably, a reduced chain α-olefin, such as methyl-9-decenoate or 9-decenoic acid, respectively. The metathesis catalyst contains ruthenium or osmium and a chelating ligand, preferably, a chelating ligand containing a carbene moiety and a second donor moiety of a Group 15 or 16 element Optionally, the catalyst can be supported on a catalyst support, such as, a cross-linked polymeric resin.
摘要:
An apparatus in accordance with this invention includes an alignment mark that is formed in a substrate. The alignment mark extends across a dice line so that, upon dicing the substrate, the mark is exposed in the substrate's side edge. The mark is formed at a predetermined distance from a position at which a feature is desired to be formed on the substrate's side edge using a mask. Accordingly, the mark is a positional reference that can be used for highly accurate placement of the feature on the side surface of the substrate with the mask. Preferably, the mark is formed of metal or other material enhanced to a size that is readily detectable by an alignment system with which the mark is to be used. The invention also includes methods for making the alignment mark.
摘要:
A longitudinal gage fixture extends the entire length of the cutting blade and provides positively locked, parallel surfaces that uniformly and reliably set the proper height of the gage blade along its length while in a blade holder, In use, the device requires no frictional movement of the gage along the length of the blade, and adjustment of the blade may be achieved in an accurate, single-step process. The entire blade and holder assembly is positioned within the gage fixture and adjusting screwy at the base of the holder are accessed through apertures in a base plate of the gage fixture so that all necessary adjustments of the blade may be made with the holder insitu without any movement of the holder. Only movement of the blade within the holder is required during adjustment. Once properly adjusted, the tightening down of the blade may also be accomplished with the blade and holder still within the gage fixture.
摘要:
In an improved process condensation polymers having terminal arylcyclobutene moieties are prepared. Such polymers are prepared by adding to a condensation polymerization process one or more arylcyclobutene chain terminating compounds along with the multi-hydric compounds and condensation polymer precursors that are typically employed in such a process. Desirably the condensation polymers have an average degree of polymerization of at least about 2, preferably at least about 3 based on multi-hydric compound. This process can be used to prepare a range of condensation polymers including polycarbonates, polyesters and polyester-carbonates. The resulting products can be easily processed and shaped into various forms and structures according to the known techniques. During or subsequent to the processing, the polymers can be crosslinked, by exposure to heat or radiation, for example, to provide crosslinked polymer compositions. These compositions have a good combination of properties, including for example, processability into shaped articles having unexpectedly good combinations of toughness, solvent resistance, ignition resistance, modulus and resistance to thermal linear expansion.
摘要:
Octahydrofluorenyl metal complexes, such as octahydrofluorenyltitanium trichloride, or ring substituted octahydrofluorenyl metal complexes wherein the metal is in the +2, +3 or +4 formal oxidation state are prepared by reduction of tetra- or hexa-hydrofluorenyl metal complexes. The reduction reaction may be carried out at ambient pressure and temperature in the presence of a catalyst. The process of the present invention permits preparation of octahydrofluorenyltitanium metal complexes from a series of high yield reactions starting with fluorene.
摘要:
A process for preparing syndiotactic vinylidene aromatic polymers comprising contacting one or more vinylidene aromatic monomers with a catalyst comprising a cationic Group 4 metal complex wherein the metal is in the +3 oxidation state formed from the corresponding metal hydrocarbyloxy containing complex in the presence of a hydrocarbylation agent.
摘要:
A process for preparing syndiotactic vinylidene aromatic polymers comprising contacting one or more vinylidene aromatic monomers with tri n-propyl aluminum chain transfer agent under Ziegler-Natta polymerization conditions.
摘要:
Imide-containing polymers of styrene-type monomers are prepared by a process comprising solution polymerizing under free radical polymerization conditions a polymerizable monomer composition comprising at least one vinylaromatic monomer and at least one maleamic monocarboxylic acid monomer.
摘要:
A process for polymerizing vinylidene aromatic monomers, such as styrene, to produce polymers having a high degree of syndiotacticity using a catalyst composition comprising a Group 4 metal complex and a hydrocarbylsilane or di(hydrocarbyl)silane catalyst adjuvant is disclosed.