In the evolution of RIM, technology appears to have preceded research; industrial practice led scholarly research and understanding. As Alberino (1982: 2) put it, "As in so many other areas, large scale commercial use of RIM preceded a full understanding of the technology from a theoretical point of view." We have already presented some evidence of this relationship in the RIM chronology and in our interview material. Analysis of RIM patents provides additional support for this conclusion, as well as offering details of the relationship between academic research and industrial development in this important process innovation.
With a search using the keywords "reaction injection molding," the U.S. Patents Database shows a total of 264 RIM patents dating from 1973 to the present, and 30 RRIM patents (these data were the basis for Figure 1, above). One means of determining the significance of patents is to count the number of times a patent is cited in subsequent patents, under the assumption that frequently cited patents are more significant than less frequently cited ones. A straightforward search of the reference sections of the 264 RIM patents shows that 1,924 patents were cited. The number of citations ranges from 29 (a 1980 patent issued to Bayer for a process for producing elastic moldings) to 1; 64 patents are cited 5 or more times. A check of the patents that have been cited 7 or more times (there were 27) shows, first, that virtually all are related to RIM and, second, that all but one were issued to private firms.[23] Prominently represented are RIM material suppliers: Bayer, Dow Chemical, Union Carbide, Texaco, Mobay, Hercules.
A crude indicator of a technology's dependence on research is
to examine the "other references" sections of patents,
which typically cite scholarly literature relevant to the patent.
The use of "other references" is neither required of
patent applicants nor invariably related to the role of research
in the patent, but previous research (e.g., Albert et al., 1991)
has indicated that, with appropriate caveats, citations in patents
to research literature can be used as an indicator of the strength
of the research-technology link in particular fields of technology
or industry. In the case of RIM patents, 107 (40.5%) have entries
in the "other references" field; in the case of the
30 RRIM patents, 16 (53.3%) have entries. A visual scan of a
sample of these sections shows that, with only a few exceptions,
these entries are actually citations to scholarly literature.[24]
These percentages compare favorably (from the point of view of
the strength of the research-technology link) with data from other
fields. Narin[25] has calculated the percentage of U.S. patents in
different industries that cite at least one public, private, or
foreign research paper, with the following results:
| Chemicals | |
| Drugs and pharmaceuticals | |
| Communications equipment and electronic components | |
| Professional and scientific instruments | |
| All SIC codes |
Allowing for possible differences in the way Narin's and our percentages
were derived, it still seems apparent that in RIM and RRIM the
research-technology linkage is relatively strong, at least according
to this measure.
According to Macosko, NSF funded work in the RIM area (mainly his work) after industry developed the technology. His initial awards in 1979 and 1982 were from the Industry-University Cooperative Research Projects program. Industry was supportive of NSF funding and wrote letters to NSF encouraging funding at universities (SRI interview with Macosko, June 3, 1996).[26] John Kardos, Director of the Materials Research Laboratory at Washington University, considers the Defense Department's role in composites to be significantly greater than NSF's; "for a long time, it was very difficult to get funds for research on composites from NSF." Kardos noted, however, that there are now NSF-supported centers at VPI (a Science and Technology Center) and Case Western Reserve (an Industry-University Cooperative Research Center). Critchfield, formerly of Union Carbide, could recall no academics other than Macosko who were involved in RIM R&D, although he identified a number of Macosko's students (who were supported by NSF) now engaged in research on RRIM and/or SRIM: James Lee and Jose Castro. The latter worked at Union Carbide during his summers in graduate school.
Andrew Bastone, President of ISARCO (an organization founded by former Owens-Corning employees to promote work in the field of composite materials, which they believe have high potential), says that current research on the manufacture of preforms for SRIM is being done primarily by industry (SRI interview with Bastone, September 13, 1996). Bastone was unable to say whether NSF had funded any academic work in the SRIM field. He said that ISARCO largely serves the needs of its industrial clients and does not have time to work with universities.
Data on the amount and significance of NSF's support of RIM-related research was obtained in several ways. First, we searched titles in the NSF awards database using keywords related to RIM. This approach yielded approximately 100 awards, using the following list of keywords:
|
|
|
| ||||
| 1985 | University of Delaware | Wilkins | Engineering Research Center for Composites Manufacturing Science and Engineering | $4,441,850 | ||
| 1989 | Virginia Polytechnic Institute and State University | McGrath | Center for High Performance Polymeric Adhesives and Composites | $5,480,110 | ||
| 1991 | Michigan State University | Hawley | State/Industry University Cooperative Research Center for Low-Cost, High-Speed Polymer Composites Processing | $1,345,168 | ||
| 1991 | Massachusetts Institute of Technology | Suh | Cooperative Agreement: Research in Processing Technology | $1,200,000 | ||
| 1992 | Virginia Polytechnic Institute and State University | McGrath | High Performance Polymeric Adhesives and Composites | $9,086,000 |
A second bibliometric approach involved use of the highly specialized Research Front Database, produced annually by the Institute of Scientific Information (ISI). The database organizes publications into clusters that, in validation studies, are seen as approximating the research specialties of working scientists. The clusters are based on the frequent association ("co-citation") of pairs of papers in the reference list of scientists publishing in journals indexed by ISI. These older, frequently cited and co-cited papers typically represent the important findings or methods that have shaped the specialty. As such, they represent the important contributions to the field.
The 1988 database was searched for RIM-related topics, and two highly relevant clusters were identified. The first was characterized by the frequent use of phrases such as REACTIVE EXTRUSION PROCESS, POLYURETHANE IONOMERS, and BLOCK COPOLYMERS in the titles of the papers indexed by ISI. The second was larger but less central to RIM, being characterized by title phrases such as POLYMER MIXTURES, EMULSION POLYMERIZATION, DYNAMICS OF POLYMER MELTS, and LINEAR VISCOELASTIC PROPERTIES.
In the first cluster, the contributory co-cited papers represented 70 authors, 40 of whom were associated with papers coming from U.S. institutions. Macosko's work appeared prominently among them, and of the 40 associated with U.S. institutions, 6 were identified as having received NSF support in the database of grantees compiled for this study.[29] In the less focused second cluster, the contributory co-cited papers represented 56 authors, 12 of whom were associated with papers coming from U.S. institutions. Half of the 12 were identified as having received NSF support.[30]
A third approach examined NSF's significance from industry's perspective. Industry led the initial development of RIM but acknowledged the need for greater understanding of the underlying phenomena (and, indeed, argued for NSF support of university research). What significance did NSF support have for industrial development of RIM? Our interviews did not reveal much useful information on this point, unfortunately. Thus we have had to rely more heavily on a less direct measure of NSF's role based on analysis of patent citations.
As described in the preceding section, a total of 64 names appeared
in the "other references" section of the highly cited
RIM patents. Twenty-seven names appeared in the "other references"
section of the 93 patents cited at least once by other patents
among the 264 RIM patents; 5 of these also appeared on the highly
cited patent names list. Of the total of 86 names cited in relatively
important RIM patents, 6 appear in the NSF awards database: Macosko,
James Ly Lee (Ohio State, and one of Macosko's former students),
Harry Frisch (SUNY Albany), Costas Gogos (Stevens Institute of
Technology), Jiri Kresta (University of Detroit), and Fred Billmeyer
(Rensselaer). To the extent that relatively important RIM patents
refer to relevant scholarly work, NSF seems well represented among
scholars cited in these patents (although we do not yet have a
basis for comparison). This information, together with knowledge
of the close ties that have existed between NSF awardees and industry
representatives via the Industry-University Research Projects
program, Industry/University Centers, Engineering Research Centers,
and Science and Technology Centers, suggests that industry is
increasing its use of academic research in the general area of
RIM (now SRIM) in which NSF has been substantially involved.
It is important to observe that RIM and, to a lesser extent, RRIM and SRIM owe their development in the 1970s and early 1980s to actions by the U.S. Congress. In the absence of automobile crash-resistance and fuel-economy legislation, it is unlikely that RIM would have developed as rapidly as it did, or that there would have been such considerable demand for RIM products. In addition to bringing substantial cost savings to auto owners through reduced repair and insurance costs, these products provided additional savings from reduced fuel consumption owing to the light weight of polyurethane. Public benefits accrued from reduced air pollution as well.
The Defense Department and NASA have supported considerable research on polymer chemistry, composites, and reinforced polymers. DOD's network of university-based Materials Research Laboratories, established in the early 1960s, was transferred to NSF in the 1970s. No doubt, research supported by these agencies contributed to greater understanding of polymer chemistry and composites, producing knowledge that benefited both the RIM industry and aerospace/defense firms. Yet our interviews revealed little evidence of interchange of knowledge between these industrial sectors; materials suppliers to RIM had problems to solve different from those of aerospace firms building high-performance polymer composites. To some extent, academic science and engineering researchers brought the disparate fields of application together, upstream, in fundamental studies of polymer chemistry.
The RIM-related research we have identified, supported by NSF
and conducted by individual investigators as well as in centers,
appears to be strongly tied to industry. Macosko was at the core
of this work in the 1980s, and his research was shaped considerably
by industry interests (recall that it was Union Carbide that first
supported his RIM research). Macosko has coauthored numerous
works with industrial researchers; his students have worked in
industry while doing doctoral study, and many have joined industry
after receiving their degrees; a considerable amount of his research
was conducted in collaboration with RIM firms. Given NSF's support
of a variety of centers conducting polymer processing research,
there continue to be strong industry-university ties in the field.
This view is supported by evidence from citations in RIM patents,
which show much greater-than-average frequency of referrals to
scholarly research.
RIM is characterized by extensive patenting of key process components: premix materials, mold release agents, and mixheads. There is no evidence that this patenting has hampered development or diffusion of the technology, nor is there evidence of extensive cross-licensing, at least in materials. Apparently, in polymer chemistry, slightly different components can have similar applications but sufficiently different compositions (and, presumably, performance) to lead to extensive patenting that does not result in market dominance by one or a small number of firms. Key RIM patents-indeed, nearly all the industrially important patents-are held by large firms, mostly materials suppliers. Bayer, already a major player in chemicals, introduced RIM and patented a mixhead design very early, but this did not lead to market dominance. Bayer had one key patent on a urea-urethane mix, and Dow had a key patent on mold release agents, and the two traded licenses. Texaco patented an all-urea mix but could not lock up the market, and sold licenses to Bayer and others (Macosko, personal communication, October 1996).
Each supplier appears to have developed proprietary formulations
that are different enough from those of their competitors for
each to enjoy satisfactory market share. One explanation may
be the diversity of RIM applications, each calling for somewhat
different performance requirements and tradeoffs between materials
costs and processing costs. Process equipment, on the other hand,
is very difficult to protect. There was a highly focused market
in automobile bumpers that is now declining. Patents in this
narrow field were weak in that they were primarily mechanical
rather than formulations.
As recently as 1990, industrial RIM users were fine-tuning their systems by trial and error. A process that began with industrial practice is continuing to be led by experimental data, rather than predictive theory. RIM has peaked; both industrial and related scholarly research efforts are focusing on reinforced RIM and structural RIM. As demand for lighter replacements for structural steel increases, the contributions that research makes to applications in RRIM and, especially, SRIM may increase accordingly.
There was incomplete, even contradictory, evidence about research-technology
relationships in RIM. On the one hand, industry representatives
whom we interviewed could not say much one way or the other about
the impact of fundamental or academic research on RIM development.
Books on RIM by industrial researchers and engineers (e.g., Becker,
Mallick and Newman) refer infrequently to scholarly research.
Yet industry representatives also concluded that fundamental
knowledge of RIM and RIM chemistry was needed but lacking. They
supported, and continue to support, academic research with their
own funds, while encouraging public support of research as well.
Evidence from patent databases shows stronger-than-average ties
between (presumably mostly academic) research and industry in
RIM. Macosko and his students interacted closely with industry,
reflecting the close ties that academic chemistry and chemical
engineering traditionally have had with industry.
We have documented the amount of support NSF has provided for
RIM-related research and traced the pattern of support over time.
We also searched for evidence of NSF's impact in our questions
to interview respondents, in citations to scholarly work in significant
RIM patents, in contributions by researchers to the ENGINEERING
database, and in clusters of RIM-related scholarly literature
defined by using co-citation analysis. Interview respondents
offered little information on the question of the influence of
academic research on RIM development. Our impression from the
remaining but limited sources of data is that NSF's role was significant.
When evidence from the remaining nine case studies is available,
we should be able to make such comparisons and draw more solid
conclusions. Nonetheless, it is clear that RIM research supported
by NSF was closely tied to industry, beginning with Macosko's
1980 award and continuing subsequently with substantial awards
to several NSF-sponsored centers.. Industry benefited by hiring
students already familiar with the process, and software based
on Macosko's NSF-supported work is now proving commercially successful.
Alberino, L. M. "Future of RIM Development in the U.S.A.," in Kresta (1982).
Albert, M. B., Avery, D., Narin, F., and McAllister, P. "Direct Validation of Citation Counts as Indicators of Industrially Important Patents," Research Policy, 20 (1991): 251-259.
Becker, W. E., ed. Reaction Injection Molding. New York: Van Nostrand Reinhold, 1979.
Boden, von Bonin, Kleimann, and Mergard. "Method of Molding Integral Skin Polyurethane Foams Having Mold Release Properties," U.S. Patent 3726952 (1973).
Castro, J. M., Macosko, C. W., Tackett, L. P., Steinle, E. C., and Critchfield, F. E. "Premature Gelling in RIM," Society of Plastics Engineering Technical Papers, 26 (1980): 423-427.
Coates, P. D., and Johnson, A. F. "An Introduction to Reinforced Reaction Injection Moulding," Plastics and Rubber Processing and Applications, 1, 3 (1981): 223-238.
Dominguez, R. J. G., Rice, D. M., and Lloyd, R. F. "Reaction Injection Molded Elastomer Containing an Internal Mold Release Made by a Two-stream System," U.S. Patent 4,396,729 (1983).
Ferrari, R. J. "Manufacturing Technology Using the RIM Process," in Becker (1979).
Harris, J. "Reaktionsguss: Ein neues Verfahren zum Herstellen Grosser Kunststoff-Formteile," Kunststoffe, 59 (1969): 398-402.
Kresta, Jiri E., ed. Reaction Injection Molding and Fast Polymerization Reactions. New York and London: Plenum Press, 1982. (Proceedings of the International Symposium on Reaction Injection Molding, sponsored by the American Chemical Society Division of Organic Coatings and Plastics Chemistry, March 31-April 1, 1981, Atlanta, GA.)
Kuerleber, R., and Pahl, F. W. "Device for Feeding Flowable Material to a Mold Cavity," U.S. Patent 3,706,518 (1972).
Lewis, G. D. "Reaction Injection Molding," in Modern Plastics Encyclopedia, 1986-1987 . Easton, PA: Breskin & Charlton Pub. Corp., 1987.
Macosko, C. RIM: Fundamentals of Reaction Injection Molding. New York: Hanser, 1989.
Mallick, P. K, and Newman, S., eds. Composite Materials Technology. New York: Hanser, 1990.
Mapleston, P. "PUR-RIM Technology Suppliers Concentrate on Reinforced Applications," Modern Plastics (June 1995): 54-62.
Newman, S. "Introduction to Composite Materials Technology: Mass Production Techniques," in Mallick and Newman (1990).
Slocum, Greg. "Reaction Injection Molding," in Mallick and Newman (1990).
Wirtz, Hans. "The Application of the RIM Process in Europe,"
in Becker (1979).
Christopher Macosko, University of Minnesota
John Kardos, Washington University
Frank Critchfield, Union Carbide (retired)
Michael Bogdan, Michigan State University
Douglas Barno, Composites Institute, formerly Owens Corning
Joel Barlow, University of Texas, Austin
Andrew Bastone, ISARCO, Owens Corning (retired)