Patents - Rockwool International A/S v Knauf Insulation Ltd.

Radomil / CC BY-SA (

Jane Lambert

Patents Court (Mr Justice Marcus Smith) Rockwool International A/S v Knauf Insulation Ltd [2020] EWHC 1068 (Pat) (7 May 2020

This was an appeal from the refusal of the hearing officer, Mr Huw Jones,  to revoke British patents GB2451719 ("719") and GB2496951("951") (see Rockwool International A/S and Knauf Insulation Limited BL 0/291/19 28 May 2019).

The Patents
The patents concern materials for holding mineral wool in place to form thermal insulation for buildings known as "binders".  Those patents had been granted to Knauf Insulation Ltd. ("Knauf").

The abstract of 719 was as follows:

"A substantially formaldehyde-free binder solutions having a pH greater than 6, comprising a carbohydrate, an acid precursor derivable from an inorganic salt and a nitrogen source. Typically, the carbohydrate is a reducing sugar, especially dextrose. The acid precursor may comprise a species selected from sulphates, phosphates and nitrates and may comprise an ammonium salt. A material comprising a collection of loose material and the substantially formaldehyde-free binder is also disclosed. The loose material may comprise mineral fibres, such as those used for thermal insulation, or may be wood board. A further material comprising loose matter and a substantially formaldehyde-free binder is also described wherein the material comprises more than 500 mg/kg of species selected from sulphates, phosphates and nitrates. The binder may comprise melanoidins. Methods of manufacturing a binder solution and a product containing loose matter are also disclosed."

The abstract of 951 was::

"A method of manufacturing a product comprises the steps of: i) Providing a collection of non-woven materials in the form of loose matter; ii) Treating the collection of loose matter with a substantially formaldehyde free binder solution having a pH of greater than 6 cothermal comprising: a carbohydrate, an acid precursor derivable from an inorganic salt which makes up at least 5% by dry weight of the uncured binder solution, a source of nitrogen and water; iii) Arranging the collection of loose matter treated with the binder solution in the form of a substrate; and iv) Curing the binder by applying a source of energy to the substrate. The product may be a mineral fibre insulation product. The carbohydrate may be dextrose; the acid precursor may be ammonium sulphate."

The IPO Proceedings 
Rockwool International A/S ("Rockwool") applied to the Comptroller-General of Patents, Designs and Trade Marks for the revocation of the patents on grounds of anticipation, obviousness and insufficiency under s.72 (1) of the Patents Act 1977.  The Comptroller appointed Mr Jones to hear the application.

In the course of the proceedings, Knauf  applied to amend claim 1 of  719 as follows: 

"A method of manufacturing a mineral wool insulation product comprising:
a) providing a substantially formaldehyde free binder solution having a pH of greater than 6 comprising:
  • a carbohydrate selected from a monosaccharide, a monosaccharide in its aldose or ketose form, a reducing sugar and a carbohydrate having a reducing aldehyde
  • an acid precursor derivable from an inorganic salt, in which the acid precursor comprises a species selected from the group consisting of sulphates, phosphates and nitrates
  • source of nitrogen; and
  • water;
in which the acid precursor makes up at least 5% by dry weight of the uncured binder solution; and
in which the binder comprises between 5%-25% by dry weight of acid precursor to carbohydrate;
b) spraying the binder solution on to the mineral fibres between formation of the fibres and collection of the fibres to form a batt; and
c) curing the binder to form a thermoset binder, in which the curing of the binder occurs in a curing oven using forced hot air circulation."

Knauf also applied to amend claim 1 of 951:

"A method of manufacturing a product selected from: a thermal insulation material a mineral fibre product; a wood board product including chip board, oriented strand board, particle board, medium density fibreboard, wood facing products; and foundry sands in which the mineral fibre product is a mineral wool insulation product, comprising the steps of:
providing a collection of loose matter comprising non-woven material mineral fibres;
applying a binder solution to the collection of loose matter by spraying the binder solution on to the mineral fibres between formation of the fibres and collection of the fibres to form a batt, the binder solution being a substantially formaldehyde free binder solution having a pH of greater than 6 comprising: a carbohydrate, an acid precursor derivable from an inorganic salt which makes up at least 5% by dry weight of the uncured binder solution, a source of nitrogen and water, and in which the acid precursor comprises one or more inorganic ammonium salts; and
curing the binder to form a thermoset binder in which the curing of the binder occurs in a curing oven using forced hot air circulation;
and in which the quantity of binder in the finished material wool insulation is greater than 1% and less than 20% measured by dry weight of the finished mineral wool insulation product."

Rockwool opposed the amendment applications on the ground that they extended the protection conferred by the patents.

Mr Jones allowed the amendments and dismissed the revocation claim.  At paragraph [83] of his decision, he said:

"I have found that the ‘719 and ‘951 patents as proposed to be amended are novel and involve an inventive step over document D3. The proposed claims do not disclose additional matter nor do they extend the scope of protection conferred. The inventions are sufficiently disclosed across the whole scope of the amended claims. I will allow the defendant to amend the claims in the manner proposed and make no order for revocation of the patents."

The Appeal
Rockwool appealed against Mr Jones's decision on the following grounds:
  • Mr Jones had erred in his assessment of the common general knowledge of persons skilled in the art;
  • He misconstrued 951;
  • He erred in assessing whether 951 was obvious over the prior art.
  • He erred in finding that 951 was plausible.
  • He was wrong to allow the amendments.
  • The amended claims were not supported.
The appeal came on before Mr Justice Marcus Smith on 4 Feb 2020.  He delivered judgment in Rockwool International A/S v Knauf Insulation Ltd [2020] EWHC 1068 (Pat) on 7 May 2020.

Conduct of the Appeal
At paragraph [13] of his judgment, the learned judge directed himself as follows:

"(1) First, in an appeal against a finding of non-obviousness, the court should only interfere with the decision below if there has been an error of principle (Actavis Group PTC EHF and others v ICOS Corporation and another  [2019] Bus LR 1318, [2019] UKSC 15).
(2) Secondly, although the parties dispensed with cross-examination of witnesses before the Hearing Officer by agreement, this did not entitle me to substitute my view for that of the Hearing Officer absent: (i) an error of principle; (ii) a failure on the part of the Hearing Officer to take account of material evidence before him; or (iii) the Hearing Officer paying regard to immaterial evidence. That said, were I to take the view that the Decision should be varied or set aside on appeal, given the absence of cross-examination by agreement, there would be no need to remit matters to the Hearing Officer.
(3) Thirdly, I should not be unduly critical of the way in which the Decision is expressed: my starting point should be that an experienced tribunal such as the Hearing Officer in this case would know how to perform his functions and what matters he should take into account" (Piglowska v. Piglowski [1999] UKHL 27; [1999] 3 All ER 632; [1999] 1 WLR 1360; [1999] 2 FCR 481; [1999] 2 FLR 763; [1999] Fam Law 617 (24 June 1999)).

The Judgment
Mr Justice Marcus Smith considered each of the grounds of appeal.

After referring to the authorities on: 
  • the skilled addressee between paragraphs [15] and [17]
  • common general knowledge [18]; and
  • obviousness [20] and [21]
he reviewed the hearing officer's decision [22] and [23] and considered Rockwool's contentions [24] to [26].  He considered the first ground of appeal to be hopeless for the following reasons:

"(1) It was common ground before the Hearing Officer that the inventive concept of the Patents was that whereas D3 taught that a sugar-based binder was derivable (amongst other things) from an organic acid, the Patents taught that a similar binder was derivable from an inorganic acid.
(2) In these circumstances, the question must be whether this inventive concept was not, in fact, inventive, because it had in fact been disclosed by D3. Clearly, the Hearing Officer, having considered the terms of D3, concluded that the inventive concept claimed by the Patents was not taught by D3. In short, the Hearing Officer resolved the question I have set out in paragraph 5(6) above in Knauf's favour. That, at least in the first instance, is a question that I should be slow to interfere with. But, moreover, this is a conclusion that is clearly correct when considering the terms of D3:
(a) I have described the Maillard reactants in paragraph 5(3) above as comprising a sugar and an amino acid. Amino acids are organic compounds.
(b) D3 refers frequently to the Maillard reactants – which is unsurprising – and to the acid element as being an "amine (i.e. amino) reactant".
(c) It is true that the summary section of D3 contains the following passage:

'With respect to the present binder's chemical constitutents, they may include ester and/or polyester compounds. The binders may include ester and/or polyester compounds in combination with a vegetable oil, suc as soybean oil. Furthermore, te binders may include ester and/or polyester compounds in combination with sodium salts of organic acids. The binders may include solium salts of inorganic acids. The binders may also include potassium salts of organic acids. Moreover, the binders may include potassium salts of inorganic acids. The described binders may include ester and/or polyester compounds in combination with a clay additive, such as montmorillonite.'

Rockwool relied on this passage, and one can see why, given the references to inorganic acids. However, it is clear from the terms of this passage that – at this point – D3 is not describing the Maillard reactants, but merely the sort of chemicals to be found in binders.

(3) Thus, considering the terms of D3 itself, the Hearing Officer had to decide whether the use of an inorganic acid – as opposed to the use of an organic acid – to produce a binder was obvious from D3. The Hearing Officer rightly concluded that it was not. The Hearing Officer specifically considered the terms of D3 and concluded that this was not so taught:
"64. …The question is whether the improvement made in the '719 and '951 Patents is an obvious one or not. In [Knauf's] view, [Rockwool's] arguments for the substitution of triammonium citrate with a sulphate, phosphate or nitrate salt are driven entirely by hindsight.
65. [Knauf] argues the because the skilled person does not have detailed knowledge or understanding of the Maillard reaction, they would not consider changing the examples given in D3 and use different acids to the citric acid when they don't know if they will work. They argue that [Rockwool's] pleading relies on combining information about the Maillard reaction from prior art from the very different field of food science.
66. Even if the skilled person did consider changing the reactants in the examples of D3, they would not consider a phosphate or sulphate. D3 provides alternative amine components to try, as shown in figure 1, which include proteins, peptides, amino acids and some polycarboxylates. However, D3 does not include phosphates and sulphates in the range of reactants to try. The only alternative to triammonium citrate is another polycarboxylic acid. While D3 makes mention of using inorganic salts, these are present as corrosion inhibitors at a maximum concentration of 2%, not as a reactant as is the case in the '719 and '951 Patent Claims (as proposed to be amended)."
(4) In these circumstances, it is impossible to see what D10 can add. D10 was, of course, known to D3: indeed, D10 was specifically referred to in D3. D10 clearly did not obviously disclose that inorganic as well as organic acids could be used to create binders, because D10 did not concern binders at all, but the browning reactions in food. In these circumstances, it is very difficult to see how D10 – not having influenced D3 in this regard – can support an obviousness argument in the context of the Patents.
(5) In short, the Hearing Officer reached the correct conclusion, and his decision is not one that I can or should interfere with. As Knauf put it in its written appeal submissions:

'…the biggest difficulty facing Rockwool was this. There was no suggestion in D3 whatever that an inorganic salt could be used in place of the polycarboxylate taught by D3. Therefore, for the invention to be obvious, the idea to use an inorganic salt had to come from the skilled person's [common general knowledge]'".

The judge rejected the second and third grounds as untenable because Rockwool had conceded to the hearing officer that if he found the ‘719 patent to be novel and inventive, then the same would be true of the ‘951 patent.

His lordship made no finding on the fifth ground because it had not been pressed on appeal.

As to plausibility, the judge cited paragraph [37] of Lord Sumption's judgement in Warner-Lambert Company LLC v Generics (UK) Ltd (t/a Mylan) and another [2018] RPC 21, [2018] UKSC 56, (2019) 165 BMLR 14, [2019] Bus LR 360, [2019] 3 All ER 9L

"Plausibility is not a term of art, and its content is inevitably influenced by the legal context. In the present context, the following points should be made. First, the proposition that a product is efficacious for the treatment of a given condition must be plausible. Second, it is not made plausible by a bare assertion to that effect, and the disclosure of a mere possibility that it will work is no better than a bare assertion. As Lord Hoffmann observed in Conor Medsystems Inc v Angiotech Pharmaceuticals Inc [2008] RPC 28, para 28, “it is hard to see how the notion that something is worth trying or might have some effect can be described as an invention in respect of which anyone would be entitled to a monopoly”. But, third, the claimed therapeutic effect may well be rendered plausible by a specification showing that something was worth trying for a reason, ie not just because there was an abstract possibility that it would work but because reasonable scientific grounds were disclosed for expecting that it might well work. The disclosure of those grounds marks the difference between a speculation and a contribution to the art. This is in substance what the Technical Board of Appeal has held in the context of article 56, when addressing the sufficiency of disclosure made in support of claims extending beyond the teaching of the patent. In my opinion, there is no reason to apply a lower standard of plausibility when the sufficiency of disclosure arises in the context of EPC articles 83 and 84 and their analogues in section 14 of the Patents Act. In both contexts, the test has the same purpose. Fourth, although the disclosure need not definitively prove the assertion that the product works for the designated purpose, there must be something that would cause the skilled person to think that there was a reasonable prospect that the assertion would prove to be true. Fifth, that reasonable prospect must be based on what the TBA in SALK (para 9) called “a direct effect on a metabolic mechanism specifically involved in the disease, this mechanism being either known from the prior art or demonstrated in the patent per se.” Sixth, in SALK , this point was made in the context of experimental data. But the effect on the disease process need not necessarily be demonstrated by experimental data. It can be demonstrated by a priori reasoning. For example, and it is no more than an example, the specification may point to some property of the product which would lead the skilled person to expect that it might well produce the claimed therapeutic effect; or to some unifying principle that relates the product or the proposed use to something else which would suggest as much to the skilled person. Seventh, sufficiency is a characteristic of the disclosure, and these matters must appear from the patent. The disclosure may be supplemented or explained by the common general knowledge of the skilled person. But it is not enough that the patentee can prove that the product can reasonably be expected to work in the designated use, if the skilled person would not derive this from the teaching of the patent."

The learned judge noted that the argument of insufficiency had been raised very late in response to Knauf's applications to amend the claims of its patents.  There was no opportunity for the parties to adduce evidence and without evidence, the hearing officer could not have been expected to rule on the point.

For all these reasons Mr Justice Marcus Smith dismissed the appeal.

Further Information
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