United States: Construing Markush Group Claims

In Multilayer Stretch Cling Film v. Berry Plastics, the Federal Circuit provided a detailed discussion of the construction of claims that use Markush group language. The decision emphasizes the closed nature of the “consisting of” terminology, and underscores the care that should be used with Markush group claim language.

The Markush Group Language At Issue

The patent at issue was Multilayer’s U.S. Patent No. 6,265,055, directed to what the court referred to as “multilayered plastic cling wrap films.” Claim 1 is representative:

1. A multi-layer, thermoplastic stretch wrap film containing seven separately identifiable polymeric layers, comprising:
(a) two identifiable outer layers, at least one of which having a cling performance of at least 100 grams/inch, said outer layer being selected from the group consisting of linear low density polyethylene, very low density polyethylene, and ultra low density polyethylene resins, said resins being homopolymers, copolymers, or terpolymers, of ethylene and alpha-olefins; and
(b) five identifiable inner layers, with each layer being selected from the group consisting of linear low density polyethylene, very low density polyethylene, ultra low density polyethylene, and metallocene-catalyzed linear low density polyethylene resins; said resins are homopolymers, copolymers, or terpolymers, of ethylene and C3 to C20 alpha-olefins;
wherein each of said two outer layers and each of said five inner layers have different compositional properties when compared to a neighboring layer.

Construction of clause (b) of claim 1 and similar language in claim 28 was in dispute. The district court construed the clause as requiring that “each of five identifiable inner layers must contain only one class of the following resins, and no other resin(s): linear low density polyethylene [(LLDPE)] resins, very low density polyethylene [(VLDPE)] resins, ultra low density polyethylene [(ULDPE)] resins, or metallocenecatalyzed linear low density polyethylene [(mLLDPE)] resins.”

Marksuh Group Claim Language

As explained in the Federal Circuit decision, “[a] Marksuh group lists specified alternatives in a patent claim, typically in the form: a member selected from the group consisting of A, B, and C," where "[i]t is generally understood that . . . the members of the Markush group . . . are alternatively usable for the purposes of the invention” (internal quotations and citations omitted). The clause at issue is “a Markush group that lists four species or types of resin—LLDPE, VLDPE, ULDPE, and mLLDPE—which are understood to be alternately useable for preparing the inner layers of the claimed film.”

The Federal Circuit Decision

The Federal Circuit decision was authored by Judge Dyk and joined by Judge Plager. Judge Taranto dissented in part. The Federal Circuit identified two claim construction issues surrounding the Markush language:

  1. whether the Markush group of element (b) is closed to resins other than the listed four
  2. whether the Markush group is closed to blends of the four listed resins

The Federal Circuit determined that the Markush language is closed in first respect, but not the second. Judge Taranto dissented as to the majority’s determination on the first issue.

In reaching its decision on the first issue, the Federal Circuit emphasized the “closed” nature of the “consisting of” phrase as compared to the “open-ended” term “comprising”:

Use of the transitional phrase "consisting of" to set off a patent claim element creates a very strong presumption that that claim element is "closed" and therefore "exclude[s] any elements, steps, or ingredients not specified in the claim." …. By contrast, the alternative transitional term "'comprising' creates a presumption that the recited elements are only a part of the device, that the claim does not exclude additional, unrecited elements."

The Federal Circuit reached this claim construction even though the specification described inner layers having an unlisted resin (LDPE), and even though several dependent claims recited inner layers that comprise LDPE. On this point, the court stated:

[T]he language of a dependent claim cannot change the scope of an independent claim whose meaning is clear on its face. …. “The dependent claim tail cannot wag the independent claim dog."

Thus, the dependent claims that do fall within the scope of claim 1 as construed by the Federal Circuit are invalid.

In contrast to its analysis on the first issue, the Federal Circuit was swayed by the intrinsic record on the second issue. The court first referred to its decision in Abbott Labs. v. Baxter Pharm. Prods., Inc., 334 F.3d 1274 (Fed. Cir. 2003):

Abbott held that if a Markush claim recites "a member selected from the group consisting of A, B, and C," the claim is presumed to permit the member to be one and only one of A, B, or C, and to exclude mixtures or combinations of A, B, and C.

However, the Federal Circuit also noted the “presumption can be overcome by a combination of other claim language and the specification itself.” Indeed, the court emphasized the overarching principle of claim construction:

All patent claims, including Markush claims, must be construed in view of "the words of the claims, the specification, the prosecution history, and any relevant extrinsic evidence."

The Federal Circuit found that in this case, “the intrinsic evidence of the '055 patent is unequivocal that the inner layers described in element (b) of claims 1 and 28 are open, not closed, to blends of the recited resins.” For example, the court noted that the specification “repeatedly and consistently references blends in describing any and all resins, including the four resins of element (b),” and discusses blending the resins in order “to achieve a desired range of physical or mechanical properties.” Finding “nothing in the prosecution history … to suggest that blends are excluded,” the Federal Circuit found “this strong intrinsic evidence” requires “the Markush group … be read as open to blends of the four listed resins.”

Choosing Your Claim Language Carefully

This decision is an important reminder of the care that should be taken with all claim language, and indicates that extra caution may be warranted whenever any “consisting of” clause is used. It is not clear whether Multilayer could have modified the Markush clause with open-ended language, such as by reciting that “the inner layers comprise a resin selected from the group consisting of ….” Some examiners raise indefiniteness rejections when a claim uses both “comprising” and “consisting of ” language, but not all combinations of such “open” and “closed” language are improper.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on Mondaq.com.

Click to Login as an existing user or Register so you can print this article.

Authors
 
In association with
Related Video
Up-coming Events Search
Tools
Print
Font Size:
Translation
Channels
Mondaq on Twitter
 
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
 
Email Address
Company Name
Password
Confirm Password
Position
Mondaq Topics -- Select your Interests
 Accounting
 Anti-trust
 Commercial
 Compliance
 Consumer
 Criminal
 Employment
 Energy
 Environment
 Family
 Finance
 Government
 Healthcare
 Immigration
 Insolvency
 Insurance
 International
 IP
 Law Performance
 Law Practice
 Litigation
 Media & IT
 Privacy
 Real Estate
 Strategy
 Tax
 Technology
 Transport
 Wealth Mgt
Regions
Africa
Asia
Asia Pacific
Australasia
Canada
Caribbean
Europe
European Union
Latin America
Middle East
U.K.
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement

Mondaq.com (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of www.mondaq.com

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about Mondaq.com’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.

Disclaimer

Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.

Registration

Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to unsubscribe@mondaq.com with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.

Cookies

A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.

Links

This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.

Mail-A-Friend

If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.

Security

This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to webmaster@mondaq.com.

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to EditorialAdvisor@mondaq.com.

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at enquiries@mondaq.com.

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at problems@mondaq.com and we will use commercially reasonable efforts to determine and correct the problem promptly.